I'd recommend putting them into a world! A couple years ago I took all my old builds form past worlds and imported them to my current server world, and it feels nice, it's like a museum of old creations and it can be fun to try incorporating old builds into new places and biomes, too. Plus I find it fun to tidy up and further decorate the areas after importing stuff, too.
Edit: Also, I'm sorry you lost your old world, I know how much it sucks when that happens. I'm glad you still have your old vehicles, atleast!