Motion · Free
Nemo
Open-source motion design and 2D animation app with keyframes and inbetweening.

An open-source motion design and 2D animation app in the browser. Timeline, keyframes, tweening, drawing tools, and storyboard work in one place. Alpha — keep backups.
On the site
- Keyframes, tweening, and inbetweens
- Drawing, layers, and document tools
- Runs in the browser, no install
- Open source, free