cacani tweening/interpolating alternatives animation tool animation generation

vpaint

http://www.vpaint.org

https://github.com/dalboris/vpaint

vgc

https://github.com/vgc/vgc

opentoolz v1.4 and later

synfig vector graphic animation:

synfig.org

2d animation tool:

https://github.com/hidefuku/AnimeEffects

http://animeeffects.org/en/