I had some free time and I wanted to make something simple suggested to me by ThePhil12. This datapack only adds one variety of Wither Skeleton, a mini-boss that spawns with double your health, can wither you from afar, and switches between enchanted bow and enchanted sword depending on how far away you stand. This was a fun idea, and it only took about an hour and a half to create, but I think it still has merit as a PvE challenge given the unique fighting style. The wither skeletons will naturally spawn, and won't replace any skeletons you had in your World previously.

To start up the datapack, simply install and then type "/function wither_warriors:start" and then you are good to go. As always, you can type "/function wither_warriors:give_spawn_egg" to give yourself a special spawn egg that spawns exclusively the so called Wither Warriors. Good luck taking them on!