The gem mod

It's a FabricMC mod for Minecraft version 1.21.5.
This Minecraft mod adds powerful gems to the game. The first gem is the Healing Gem, which makes you invulnerable for one minute. If you sneak, the entities around you cannot move for a while.
There is also an Air Gem, which makes entities around you fly upwards. If you sneak, you get a boost that lets you glide downwards.
The third gem lets you create a maze-like attack area and knock back entities around you.
The fourth gem is the teleportation gem. This gem gives you an infinite supply of ender pearls, and sneaking gives you a chorus fruit.

The command /gem start/drop/settings/save lets you do a couple of things.
With /gem start, you can place a structure at the world spawn point, and with /gem drop, all of the gems appear at the world spawn.

To customise things further, use the command /gem settings .

Please make sure that if you have customized some things you have typed in /gem save!

The idea is from the mystic SMP and the videos are here (it's a german project).