Glaxnimate is a simple and fast vector graphics animation program.
qStopMotion
qStopMotion is a fork of stopmotion for Linux.
Dust3D
Dust3D is a cross-platform open-source 3D modeling software.
Enve
Enve is a new open-source 2D animation software for Linux.
VPaint
A glimpse into the future of Graphic Design and 2D Animation
Synfig
Professional open-source 2D Animation Software for Linux.
Pencil2D
An easy, intuitive tool to make 2D hand-drawn animations.