What are some alternatives?
When comparing TVPaint Animation and Pencil2D, you can also consider the following products
OpenToonz - OpenToonz is an animation program that is a free software version of Toonz, the animation software...
Synfig Studio - Just another WordPress site
Adobe Animate - Adobe Animate is a Flash, vector animation software.
Toon Boom Harmony - Production-ready animation software for every artist, in any style.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Pencil - Pencil is an animation/drawing software for Mac OS X, Windows, and Linux.