Any cool game modes I can play on vanilla Minecraft?

My friend and I are making a new server and we're looking for a cool game mode to play that we can make with commands or something like that. Some examples are infinite darkness, skyblock, survival island, stuff like that.

Superflat survival is a great one if you can create more villages and develope trade while maximizing resources to create a trade system all the while making a home base on flat ground with what you trade for. Hope this helped