Here are a few lightweight web animation services:
- Motion.Page — a timeline-based animation suite in the form of a WordPress plugin — very impressive interactive features delivered on a web page with a light payload — code for each animation loads only on pages where used
- GreenSock (GSAP3) — if you want to get programmatic with the API behind Motion.Page
- Ccover — free stock video footage for web page backgrounds, etc.
- Mesher by CSSHero — create cool CSS Mesh backgrounds