Vanilla animations are stiff and robotic — everyone walks, fights, and idles the same way. The animation stack fixes that: FNIS or Nemesis runs the behavior engine, XPMSSE is the skeleton, and CBPC/FSMP add physics. Expressive Facial Animation gives NPCs actual faces. Install the skeleton first, then the behavior engine, then the animations.
Ranked by hand, not auto-generated. Every mod links to its full page with install guide + compatibility.