Wandering minibosses

While there are currently really only a few 'minibosses' or random miniboss battles such as pillager raids/pillager outposts or the mansion, or elder guardian or warden but they really aren't classified as such, even though they should, but we need more of that. Such as maybe elemental creatures that could drop some very special things or maybe just some stronger variants of the current hostile mobs, passive mobs can also get a miniboss variant, such as the pig whos variant could be like a hog or warthog-like creature. They could have some interesting lore behind them too, obviously shown to us through future updates