Animations

Minecraft seems to have a bunch of amazing ways to add animations to mobs without the need of client sided mods.

However, first person animations or player animationss in general are very difficult to implement, I personally have only seen it done with shaders or using a plugin that makes the player invisible and plays a custom model, but both have their limitations.

First being that certain popular mods such as sodium may break your first person animations

and second being that all your cosmetics such as armor will disapear when you attack, as well as, because the animation is playing over your character it forces third person or your screen gets filled with the model that gets spawned.