Why can't I filter on minecraft version?
I have purposely not included filters for Minecraft versions as the version information on litematics is often unreliable. In many cases only tested on the version of Minecraft the creator was on and it's very rarely updated to reflect newer versions of Minecraft.
If you find a litematic you like then the best thing to do is download it then paste it into a creative world to test.
As well if you test it in a version of minecraft and find it works, hit the feedback button and leave a helpful comment for other users.