I heard that there is a Medrash that says that besides Noach, his wife, 3 sons, 3 daughters-in-law, animals, birds, and garbage there were others in the Teiva. What else was in the Teiva?
There were 'mazikim' that entered the teiva (Rashi, 6:19)
also Og the king of Bashan was holding the teiva from outside and was swimming on it like on a float (or was sitting on it)
Besides for the Pair of Ravens the Netziv says that Noach had a Private raven. This was apparently the way of royalty to have one raven and one dove.
Both Rabeinu Bachai (Bamidbar 21:34) and the Maharsha (Nidda 61A) say that Cham's wife committed adultery with Shamchzi and then gave birth to Sichon (Og's brother) in the teivah.
Just found a Yalkut Shimoni on Parshas Noach that mentions that Sheker wanted to come into the Teiva. Noach would not let him in as he had no pair. So Sheker cut a deal with Pichsa (tragedy) to join him in the Teiva. In exchange they made up that anything earned through Sheker would have a tragic end.
Food, but that's not a medrash.