Where the recipient doesn't want the gift: Gittin 21a
The transfer of a gift of money requires pulling the money: Gittin 13a
Validity of a gift which is predicated upon the return of the item: Succah 41b; Kiddushin 6b
Designating a gift before 3 parties, without writing it in a bill or actual transfer: Gittin 13a, 13b-14a
Reneging on the above deal: Gittin 14a
Legal Power of a Gift Recipient
Can a giver renege on a pledge to give a small or large gift: Bava Metzia 49a
The claim of a purchaser of an item to prevent its collection by one who has a claim on the seller, is weaker than the power of a claim by one who received the item as a gift: Bava Metzia 15a
The potential ownerlessness of property which one person attempts to give to another, but the intended recipient declines to accept: Keritot 24a-b