Retained mode was deeply unpopular even back when it was supposed to be the flagship API, for good reasons (it was slow as hell), so the games that relied on it for support can literally be counted on both hands.
That aside, the only other old game API that I can think of that's gone for good is DirectPlay, which generally means no multiplayer for games that depend on it as the only option, but otherwise doesn't affect them.
That aside, the only other old game API that I can think of that's gone for good is DirectPlay, which generally means no multiplayer for games that depend on it as the only option, but otherwise doesn't affect them.