R' Nachman ben R' Tzvi Aryeh Goldstein of Tcherin ZY"A, one of the greatest Breslov leaders. Grandson of Reb Ahron, the Rov of Breslov. His sforim include Parparos Lechochmah on Likutei Mohoran, Leshon Chasidim and Derech Chasidim on teachings of the Baal Shem Tov and talmidim, Likutei Eitzos Hameshulosh and more. Passed away in 1894.
R' Moshe ben R' Dovid Feinstein ZY"A - Nothing more needs to be said than just "Reb Moshe" and it's known exactly who you're talking about. Loved by everyone. Besides being a Gaon in Torah he was know for his tzidkis bein adam Lemokom and bein adam lechaveiro. His Igros Moshe responsa can be found in virtually every Bais Hamedresh. As much as I write it would not do him justice so I will let whoever is interested in more info get it online or from his biography.
R' Shlomo Strashun of Vilna ZY"A, wrote the famous commentary on Shas- Rashash, not to be confused with R' Sholom Sharabi