A bill of divorce may not contain a condition which will bind the two together: Eruvin 15b; Succah 24b; Nedarim 5b; Gittin 9a, 21b; Kiddushin 5a
Utilizing a condition if Divorce is to occur Post-Mortem: Ketuvot 2b
Isolation of husband and wife together, where a Bill of Divorce was given to take effect just before his death: Ketuvot 27b
A Bill with a condition that it will only take effect just before his death: Succah 23b; Nedarim 3b-4a
Problems with a Condition for a Get
What if Unavoidable Circumstances prevent fulfillment of the Condition: Ketuvot 2b-3a; Nedarim 27a-b
Whether Unavoidable Circumstances are considered "expected": Ketuvot 2b
If he dies before the time-span of the Condition for preventing the Bill from taking effect: Ketuvot 2b
Bill with a retroactive Condition, where he dies during the Condition period: Ketuvot 2b
Don't allow claims of Unavoidable Circumstances on a Condition, because modest women might assume Unavoidable Circumstances and not remarry: Ketuvot 2b-3a
Don't allow claims of Unavoidable Circumstances on a Condition, because non-modest women might claim there weren't Unavoidable Circumstances where there really were: Ketuvot 2b-3a
What if a man is dying, and he offers his wife a get, but first she says, "Don't worry; if you live, I am still yours.": Bava Metzia 66a
The conditional bill of divorce used in King David's armies