Apocalypse's are great and all (Eldritch doomsday in
Look Outside would be my pick for being creative and haunting). But my favorite apocalyptic concept is the post-post-apocalypse. It seems rare, but is always interesting when it occurs.
Luke Humpfris makes a bunch of shorts on youtube that have this idea in mind.
I thought I had more examples in mind, but the gamecube/dreamcast game
Skys of Arcadia is the last one I can think of right now

. In that setting the world got blasted asunder sometime in the far distant past, leaving only shards of land infused with moonstones (magic floaty rocks) behind. Essentially nobody knows that the world experienced a horrific catastrophe in the past as it was so long ago, all they know is their life among the clouds. It makes the setting feel more hopeful while still having major "Oh shit!" moments, especially as you learn more of the nature of the disaster from ancient ruins.
Edit: Just remembered
Horizon: Zero Dawn I knew there was a big one I forgot! Honestly probably the best example for how cool a post-post-apocalypse can be. (might still count as just post-apocalyptic, but it gets the feeling right)
A
Fallout setting far in the future, where the threat of radiation has become rare, would be interesting to me. Would the Brotherhood of Steel change their stance on technology as the world no longer bears the mark of the risk high-tech brings? Are vaults just a thing of legend now, being buried under years of dust and dirt from new plant growth? Have mutants developed into anything new beyond deformities?
The post-post-apocalypse setting just feels like you can do tons of cool ideas with it, plus it can be nice exploring ruins reclaimed by nature.