Rosh Chodesh - 1 Av
The death of tzadikim is compared to the burning of the Beis HaMikdash. Perhaps, that is why there is such an disproportionate amount of tzadikim that were niftar on this day, Rosh Chodesh of the month when the first and second Beis HaMikdash were destroyed, starting with Ahron HaKohen, the "ohev Shalom v'rodef Shalom", which in turn is related to the churban.
1 Av - Ahron HaKohen (1272 B.C.E)
1 Av - Elazar ben Ahron HaKohen
1 Av - R' Yehoshua Heschel ben R' Elazar (died early 1700's) was the Rov of Dubna after R' Yosef Yoska, the Yesod Yosef
1 Av - R' Noson Nota ben R' Yosef of Averitch (1785) Talmid of the Baal Shem Tov and father-in-law of the Bas Ayin. He did not sleep on Shabbos because it says "V'shomru Bnei Yisroel es HaShabbos", you should watch the Shabbos.
1 Av - R' Asher Wallerstein (1837) was the son of R' Aryeh Leib, the Shagas Aryeh,
1 Av - R' Ahron ben R' Moshe Goldstein (1845) was the Rov of Breslov. He was one of the main students of R' Nachman of Breslov. R' Nachman said that he used his ancestral merits to bring R' Ahron to Breslov and that R' Ahron went to his chuppah with a "clean garment". He and R' Naftali were the two witnesses to R' Nachman's famous promise to pull out of Gehinom anyone who gives tzedaka and says Tikun HaKlali by his kever. His son, R' Tzvi Aryeh succeded him and R' Tzvi's son was R' Nachman of Tcherin.
1 Av - R' Shmuel ben R' Dovid Tzvi Ehrenfeld (1883), the Chasan Sofer, grandson of the Chasam Sofer
1 Av - R' Ahron ben R' Chaim Halberstam of Sanz (1903)
1 Av - R' Menachem Nochum of Kobrin-Bialystok (1918) ben R' Yehudah Leib was a talmid muvhak of the Yesod Avodah of Slonim
1 Av - R' Shlomo ben R' Ben-Zion Halberstam of Bobov (2000) His father, first wife and several children were murdered by the Nazis y's. He remarried after the war and rebuilt Bobov into one of the largest chassidish communities in the world. His only son to survive the war, R' Naftal Tzvi, sucseeded him and passed away in 2005. There is a book, Nor the Moon by Night, about his experiences during the Holocaust. It was mentioned many times after his passing that it was no coincidence that his yahrzeit is the same as Ahron HaKohen's because he was consumate "ohev Shalom v'rodef Shalom" and was loved by all.
2 Av - R' Ahron Teumim HY"D (1690) ben R' Moshe, was the Rov of Kracow. While visiting another region, a Polish nobleman had him arrested for no reason, and placed on a horse to bring him to jail. On the way, he fell off many times and they put him right back on until he died from his wounds.2 Av - R' Moshe ben R' Avrohom Stern (1997), Debreciner Rov, author of Be'er Moshe. One of the greatest poskim of our time.
3 Av - Reb Shimshon ben R' Pesach Ostropolier HY"D See here for more.
3 Av - R' Gedalia Ahron Rabinowitz of Monastrich HY"D (1919) ben
3 Av - R' Yehoshua was killed in a pogrom in Uman with 700 others.3 Av - R' Dovid Shapira (1934) ben R' Pinchas Leib3 Av - R' Chaim Yechezkel Taub of Ozorov (1938) ben R' Yisroel of Modzitz3 Av - R' Yitzchok (1941) ben R' Mordechai Twersky of Skver-Kishinev was the first Skverer Rebbe in America.3 Av - R' Yehoshua Heschel HaLevi Horowitz HY"D (1943) ben R' Chaim Shmuel was a descendant of the Chozeh of Lublin.
4 Av - R' Menachem Azariah ben Yitzchok Brechya (1620) Rama MiPano
4 Av - R Tzvi Meir HaKohen Rabinowitz, Av Beis Din of Radomsk (1902) His father was the Tiferes Shlomo, R' Shlomo HaKohen of Radomsk
4 Av - R' Ephraim Taub of Kuzmir (1904) ben R' Yechezkel
4 Av - R' Benzion Halberstam HY"D (1941) ben R' Shlomo, Bobover Rebbe, author of Kedushas Tzion. See Heichal HaNegina for more.
5 Av - R' Yitzchok ben R' Shlomo Luria Ashkenazi, The Arizal (1572), The Chida said on him that the way he reached such a high level was that Eliyahu HaNavi purified him with ashes of a Parah Adumah. The Arizal is respected and accepted by all the great Rabbonim of the Ashkenazim (chassidim and non-chassidim), Sefardim and Teimanim. Besides Kabbalistic Seforim, the Arizal is very often quoted in halachic works, such as the Magen Avrohom, Be'er Heitiv and Mishna Berura.
5 Av - R' Gedalyah Chiyun (1750), founder of Yeshiva Beis El which studied Kabbalah based on the Arizal
5 Av - R' Chaim of Krasna (1793) talmid of the Baal Shem Tov
5 Av - R' Chaim Ozer Grodzinsky of Vilna (1940) author of Achiezer. One of the Gedolei Hador of his time, he was very close with the Chofetz Chaim. He was a great tzadik and an absolute genius, with a reputation, for among other things, being able to write two separate things at a time using his right and left hand simultaneously.
5 Av - R' Binyomin Paler (2000), talmid of the Brisker Rov, and founder of Yeshiva Bais Hatalmud and Yeshiva Mekor Chaim
5 Av - R' Yechiel Michel Dorfman (2006) One of the leaders of Breslov. He married the granddaughter of R' Avrohom Sternhartz. It seems like yesterday that we were davening for a refuah sheleima for R' Yechiel Michel ben Chana Perel. He used to risk his life to take people to Reb Nachman's tzion in Uman. Spent time in Russian prisons and Siberia. Till the end he had a rigorous schedule of Torah and Avodah.
6 Av - R' Yehoshua Greenwald, Av Beis Din of Chust
6 Av - R' Shlomo Zalman Hanau of Frankfurt-on-Main, author of Binyan Shlomo
7 Av - R' Pinchos of Sokolivka HY"D (1919) ben R' Gedalia Ahron of Linitz He was killed by the Ukranians.
7 Av - R' Sholom Noach ben R Moshe Avrohom Brezovsky (2000), Slonimer Rebbe and author of Nesivos Sholom, one of the most popular Chassidishe Seforim of our time. He was a son-in-law of the previous Rebbe, the Birchas Avrohom. See Heicha HaNegina for more.
7 Av - R' Moshe Greenwald of Chust, the Arugas Habosem
7 Av - R' Simcha Bunim Ehrenfeld of Mattersdorf
8 Av - R' Simcha Zissel Ziv of Kelm (1898)
9 Av - Reb Yaakov Yitzchok ben Reb Avrohom Eliezer Halevi, the Chozeh of Lublin See here for more.
9 Av - Reb Gavriel "Malach" ben Reb Dovid Horowitz of Moglenitza(1858) was a talmid of the Ohev Yisroel of Apta, Magid of Koznitz and his son, Reb Moshe Elyakim Briah and Reb Chaim Meir of Moglenitza. He helped put together the writings of the Magid of Koznitz
9 Av – R’ Yitzhak Nisim ben Rachamim, Sephardi Chief Rabbi of Israel (Rishon Letzion) from 1955 to 1972 Rebbe of R’ Mordechai Eliyahu
10 Av - Yissachar ben Yaakov Avinu
10 Av - Don Yitzchok Abarbanel (1508)
11 Av - R' Hillel ben R' Meir HaLevi Malisov, best known as Reb Hillel Paritcher (1864) was a talmid of the Bas Ayin, Chenobyler Magid, Miteler Rebbe and Tzemach Tzedek. He was one of the greatest tzadikim in Chabad at the time and was like a Rebbe in his own right. He authored Pelach Harimon, Imrei Noam, Likutei Biurim and Maamar Hishtatchus.
11 Av - R' Yitzchak Blazer of St. Petersburg (1907) was a talmid of R' Yisroel Salanter. He wrote Ohr Yisroel, based on his Rebbe's letters and Pri Yitzchok (1907)
12 Av - R' Aryeh Leib Katzenelbogen (1837) Rov of Vilna
12 Av - R' Moshe Ber ben R' Ahron of Stolin (1847) was a grandson of R' Shlomo of Karlin
12 Av - R' Ephraim Zalman ben R' Menachem Manish Margolies(1886) son-in-law of the Trisker Magid
12 Av - R' Yeshayahu ben R' Avrohom Moshe Veltfried of Kalish (1939)
13 Av - R' Nosson Nota Shapiro of Krakow (1633), author of Megaleh Amukos
13 Av - R' Mordechai ben Avrohom Benet (1829), author of Techeiles Mordechai
13 Av - R' Yehuda Leib Pesach ben R' Avrohom of Lipsk (1865)
13 Av - R' Yaakov Dovid ben R' Menachem Mendel (Tzemach Tzadik) Hager (1865)
13 Av - R' Yosef of Chelm ben R' Mordechai "Mayim Amukim", talmid of the Chozeh
13 Av - R' Yisroel Shmuel ben R' Aryeh Leibush of Tamoshov (1869) grandson of R' Yosef of Chelm, whose yartzeit is the same day.
13 Av - R' Yaakov Yosef ben R' Moshe of Orzetchov
13 Av - R' Eliyahu Maaravi (1955) was a great leader of Mekubalim in Yerushalayim.
13 Av - R' Yosef Eliyahu Henkin (1973), posek and head of Ezras Torah. He is buried on Long Island in Beth David Cemetery, Elmont, NY.
13 Av - R' Yosef Greenwald of Pupa (1984) ben Yaakov Chizkiya , author of Veyechi Yosef
14 Av - R' Tzvi Hirsch ben R' Ahron Friedman of Liska (1874), talmid of the Divrei Chaim and Rebbe of R' Shayele Kerestirer. He wrote Ach Pri Tevuah
14 Av - R' Yitzchok of Mezritch (1826) talmid of the Chozeh
14 Av- R' Yitzchok Friedman of Bohush (1992) ben R' Sholom Yosef of Shpikov, Rebbe from the Rizhin Dynasty
15 Av - Nochum Ish Gamzu, tanna who was known for saying "gamzu letovah" for everything
15 Av – R’ Shimon Libya of Tripoli (1585) author of Kesem Paz on Zohar and composer of the famous song “Bar Yochai”
15 Av - R' Amram ben Divan was a great Morocan Tzadik
15 Av - R' Asher (the second)(1873) ben R' Ahron (the second) of Karlin
15 Av - R' Yaakov ben R' Mordechai Yosef Leiner of Izhbitza-Radzin (1878), author of Beis Yaakov
15 Av - R' Meir Noson ben R' Chaim (Divrei Chaim) Halberstam (1855) was the father of the first Bobover Rebbe
15 Av - R' Dovid Yosef ben R' Shlomo Yechiel Biderman of Lelov (1897) He was from the members of the Lelover family that didn't move to Eretz Yisroel. He was Rebbe in Lelov, Poland
15 Av - R' Tzvi Hirsch Halberstam of Rudnik (1918) ben R' Boruch of Gorlitz, grandson of the Divrei Chaim
17 Av - R' Shlomo Chaim Perlow of Koidenov (1862) was the son of R' Ahron, the son of R' Mordechai Yaffe of Lechovitch. They were direct (ben acher ben) descendants of the Levush. He was raised by his maternal grandfather, R' Asher Perlow of Karlin, after his father died, and therefore he is also known by the last name of Perlow. After his uncle, R' Noach of Lechovitch, died, all the chassidim flocked to R' Shlomo. He had several sons that became great Rebbes in their own right.
18 Av - R' Shlomo Chanoch HaKohen of Radomsk HY"D ben R' Yechezkel. A great-grandson of the Tiferes Shlomo, he was murdered in Warsaw in 1942.
19 Av - R' Yaakov ben R' Machir Culi, author of Me'am Loez (1732) Here is an article on him, by R' Aryeh Kaplan.
19 Av - R' Naftali be R' Yehuda of Nemerov (1860) One of the closest talmidim of Reb Nachman of Breslov and one of the two witnesses to the promise about reciting Tikun HaKlali at R' Nachman's kever.
19 Av - R' Shimon Sholom ben R' Menachem Kalisch of Amshinov (1954)
19 Av - R' Menachem Nachum ben R' Yitzchok Friedman of Boyan (1936)
20 Av - R' Yehuda Zerachya Azulai (1870) was a great-grandson of the Chida
20 Av - R' Eliezer of Uzipoli (1865) ben R' Yehuda Tzvi of Stretin
20 Av - R' Levi Yitzchok ben R' Boruch Schneur Schneerson (1944) was father of the last Lubavitcher Rebbe, R' Menachem Mendel.
21 Av - R' Chaim ben R' Yosef Dov Ber Soloveitchik, Rosh Yeshiva of Volozhin and Rav of Brisk (1918)
21 Av - R' Ahron ben R' Yisachor Dov Rokeach, the Belzer Rebbe (1957) From the greatest tzadikim of his time. The numerous stories of his tzidkus and miracles are legendary. Many of the great tzadikim in Eretz Yisroel, from all segments, were very close to him. He lost his whole family to the Nazis y's. The fascinating story of his escape can be read in Rescuing the Rebbe of Belz.
21 Av - R' Alexander Sender of Komarna (1818) ben R' Yitzchok Issac was a talmid of the Chozeh of Lublin
21 Av - R' Dovid Hager of Zebultov (1848) ben R' Menachem Mendel of Kosov was a son-in-law of R' Moshe Leib of Sasov. He wrote Tzemach Dovid.
22 Av - R' Mordechai ben R' Hillel, the "Mordechai"HY"D (1298) killed during the Rindfleisch pogroms
22 Av - R' Meir Hagadol of Premishlan (1773) ben R' Yaakov "Tam" was one of the great talmidim of the Baal Shem Tov. The Nadvorna dynasty, with it's many offshoots descend from him. His grandson was the famous R' Meir'l of Premishlan
22 Av - R' Eliyahu Dushnitzer (1949), mashgiach of Lomza Yeshiva, Petach Tikva. The Chazon Ish is reported to have said that he was one of the 36 "hidden tzadikim". He was a talmid of the Chofetz Chaim and one of the ones chosen to get the dibbuk out of a woman, in the well know story told over by R' Elchonon Wasserman.
23 Av - R' Yaakov Yisroel ben R' Chaim Peretz Kanievsky, the Steipler Gaon (1985), author of Kehillas Yaakov. His father was a chosid of R' Yaakov Yisroel of Cherkass, and named him after his Rebbe. The Steipler's son R' Chaim shlita is one of the Gedolei Hador today.
24 Av - R' Ephraim Zalman ben R' Menachem Margolies (1828), Av Beis Din of Brod and author of many sefarim, including Beis Ephraim, Olelos Ephraim and Mateh Ephraim, which is perhaps most famous, contains all the halachos pertaing to Elul and Tishrei. (1828)
25 Av - R' Yeshayahu Menachem ben R' Yitzchok of Cracow (1599), originator of the Heter Iska
26 Av- R' Yaakov Meshulam Orenstein (1839), Rov of Lvov and author of Yeshuos Yaakov
26 Av - R' Yehuda Fatiyah (1942) was a talmid of the Ben Ish Chai.
26 Av - R' Yoel ben R' Chananya Yom-Tov Teitelbaum (1979), the Satmar Rebbe, author of VaYoel Moshe and Divrei Yoel, he is buried in Kiryas Joel (Monroe), NY.
26 Av - R' Meir Ashkenazi (1954) Rov of Shanghai
26 Av - R' Eliyahu Baruch Goldschmidt, Mashgiach Ruchni Yeshiva Gedolah Zichron Moshe of South Fallsburg (2000)
27 Av - R' Yehoshua Charif of Cracow, author of Maginei Shlomo (1648)
27 Av - R' Naftali Tzvi Yehuda Berlin (1893) the Nitziv, Rosh Yeshiva of Volozhin, he married the grandaughter of Reb Chaim Volozhiner, author of Ha'emek davar, Ha'emek She'ela and Meshiv Davar
27 Av - R' Yehuda Fattiah, Iraqi Gadol and mekubal, author of Beis Lechem Yehuda (1941)
27 Av - R' Yehuda Pettiyah (1942) was a great mekubal and author of 15 seforim, including Beis Lechem Yehuda and Yayin HaRokeach
27 Av - R' Shmuel Tzvi Hirsh Horowitz, known as Reb Heshele of Spinka (1997)
27 Av - R' Avrohom Mordechai ben R' Yitzchok Meir Alter, son of the Chiddushei Harim, father of the Sfas Emes
28 Av - R' Avrohom Yaakov ben R' Meir HaKohen Pam (2001) was the Rosh Yeshiva of Torah Vadaas and founded the Shuvu organization. He was one of those that was loved by all. He is buried in Mount Judah Cemetery in Queens, NY.
29 Av - R' Shmuel ben R' Yosef Zundel Salanter (1909) Rov of Yerushalayim.
29 Av - R' Menachem Mendel Alter HY"D (1942), Went to his death in Treblinka with "yishuv hadaas, tzidkus and prishus". He was a son of the Sgas Emes, R' Yehuda Aryeh Leib.
29 Av - R' Eliezer Zusia ben R' Yisroel Avrohom Portugal (1982), the Skulener Rebbe was a talmid of the Stefanishter Rebbe. After moving to the USA he founded the Cheseed L'Avrohom orginization. He is buried in the Vizhnitzer Cemetery in Monsey, NY. His son, R' Yisroel Avrohom, the present Skulener Rebbe, is one of the most respected tzadikim around today. See the story: Shachris with the Skulener Rebbe Brings Success.