Orochimaru, he did so many things with his life that mentioning them all at once is impossible.
Tsunade, she's Hashirama's grand daughter and contains his blood that has supernatural powers to it, and she pioneered the whole medical system, and invented/improved on an unbeatable technique that surpasses even RSM levels of Chakra, and Power by feats.
Jiraiya, not much to say since he was the major most center-spotlight acquiring character in the whole series, he was brought by Juubito, and Pain, and Kisame, and Itachi, and Obito (Masked) which gives off the vibe he was well respected and had all eyes on him during his lifetime. He passed the Frog Summons and introduced Minato to Mount Myoboku, which gave him his greatest power and made him the almost unbeatable powerhouse he is today and his son.