Spawners that spawn items inside themselves they can also be upgraded and mined with a Silk Touch pickaxe

Spawners don't drop experience.

Mobs do not appear using spawners.

BarrelShulkers is a lightweight server-side plugin for Minecraft 1.21.4 that turns vanilla barrels into fully functional shulker boxes. With this plugin, every barrel placed in the world behaves exactly like a shulker box it can be broken and picked up

SlimeSnowball is a fun and lightweight server-side plugin for Minecraft 1.21.4 that lets you throw slimeballs to slow down your enemies — just like snowballs, but stickier!

OONTuda is a chaotic and hilarious server-side plugin for Minecraft 1.21.4 that adds a unique consequence to player kills.