I found a Purpur server running on 1.21.11 and it is all about letting players use stasis glitches.
The main thing people ask about is getting the fishing rod stasis glitch working by changing the right lines in the yml files. This place feels like it is for players who like testing weird Minecraft mechanics and messing with server settings to make them possible.
Enable Fishing Rod Stasis Glitches

GG.MINEWIND.NET New Server IPGlitchy Modded Chaos Server

This is a modded Minecraft server with a custom pack made by the owner. Stuff is kind of broken on purpose or at least it feels like that.
You cannot sleep at night even when it is clearly dark so you just have to deal with it. The light also looks messed up so things feel really cursed when you walk around.
In the nether piglins even zombify which is super weird and makes it feel like the whole world is bugged out. If you like strange glitches and a server that does not act normal this one is actually pretty fun to watch and try.
GG.MINEWIND.NET New Server IP
