If the eved stays beyond the Sabbatical year: Kiddushin 4a
An Eved Kenaani
Concern about feeding a kohen's eved terumah, since the kohen may find something about the eved to disqualify the transaction and may indeed reverse it: Ketuvot 57b-58a
If the eved runs away: Gittin 12b-13a
An eved whose owner has declared him free, but who still lacks a formal document of freedom: Keritot 24b
Whether a female eved may eat terumah of the master: Kiddushin 10b
Giving an eved terumah without his master present: Ketuvot 28b