Best Way To Animate 2D Sprites?

Hi! I was going to start making sprites for a 3d game, but I thought, how would you animate it? Is there a way to give the sprites bones like 3d models or do you make many frames, or a sprite sheet it is refereed to, and make your changes each frame to make his animation. Which is the best\fastest/easiest?

We are working on animation support for 2D characters. For now, you could

  1. Attach it to a transform and animate it with the Animation window and blend them using mecanim
  2. With the help of packages like Puppet2D
    or do it with an external tool like Spine or ToonBoom.