Open-source 2D animation software.
Synfig Studio is a free and open-source vector-based 2D animation software. It is created by Robert Quattlebaum with additional contributions by Adrian Bentley. Synfig began as the custom animation platform for Voria Studios, and in 2005 was released as free/open source software, under GNU GPL-2.0-or-later.

NOTE: This is only to provide appimages, I am not the developer.