Preparing For Rosh Hashana Already

The Satmar Rebbe, Reb Yoel Teitelbaum, used to say in the name of his father, the Kedushas Yom Tov, that when we read in Parshas Naso נָשֹׂא אֶת רֹאשׁ – "רֹאשׁ" is a reference to Rosh Hashana, telling us that we already need to start preparing ourselves for Rosh Hashana.

Rosh Chodesh Sivan - Yahrzeits

R' Eliezer David Greenwald of Satmar (1928) author of Keren L'David

R' Yechiel Aharon ben R' Dovid Leifer (2000), the Bania-Nadvorna Rebbe of Tzefas

26 Nisan - Shabbos - Yahrzeit of Yehoshua bin Nun, Machaneh Ephraim, Satmar Rebbe

Yehoshua Bin Nun (1243 B.C.E.)

R' Efraim Navon, Rov of Constantinople, and author of Machaneh Ephraim
(1735)

R' Nachman of Tulchin ben R' Avrohom, Talmid of R' Noson of Breslov

R' Moshe ben R' Chaim Tzvi Teitelbaum, Satmar Rebbe - First Yahrzeit

19 Adar - Yahrzeits

R’ Yosef Chaim ben R’ Avrohom Shlomo Sonnenfeld ZY”A, Rov of Yerushalayim (1932). Talmid of Ksav Sofer

R’ Yehuda Greenwald ZY”A, Av Beis Din of Satmar, author of Shevet
MiYehuda

R’ Yitzchok ben R’ Yosef Kalisch ZY”A, Amshinover Rebbe of US (1993)

R’ Meir Yechiel ben R’ Avrohom Yitzchok Halevi Haldshtok ZY”A, Ostrovtzer Rebbe (1928) Not so well known, but was an absolute genius besides being a great tzadik who fasted most of his life. There is a great tape about his life from Rabbi Berel Wein, available here. Wrote Meir Einei Chachomim (not to be confused with an earlier sefer on Chanukah & Purim by R’ Meir of Kursetchov)

29 Shvat - Yahrzeits for Shabbos - Kedushas Yom Tov & Alter of Slabodka

9 Shvat is the yahrzeit of Reb Chananya Yom Tov ben Reb Yekusiel Yehuda (Yetev Lev)Teitelbaum ZY"A. He wrote the sefer Kedushas Yom Tov. His sons were the Satmar Rebbe, Reb Yoel ZY"A, and the Atzei Chaim, Reb Chaim Tzvi ZY"A. (Note: many places list his name as Chananya Yom Tov Lipa, but this seems to be an error because on the Satmar Rebbe's matzeiva and in his sforim it doesn't say Lipa.)

Also, yahrzeit of the Alter of Slabodka, Reb Noson Tzvi Finkel ZY"A. See here for more info and a beautiful picture of his hadras ponim.