Open-source alternatives to Adobe After Effects

2 community-reviewed projects you can use instead of Adobe After Effects.

1. Synfig Studio - Synfig Studio is a free and open-source 2D animation program designed for creating film-quality animation from vector and bitmap artwork, using vector tweening to generate smooth movement automatically, with 50+ layer types, a bone system for cut-out animation, and advanced controls. Available for Windows, macOS and Linux. (Licence: GPL-3.0)
2. Natron - Natron is a free and open-source node-based compositing application for visual effects and motion graphics, modelled on Nuke's workflow, with keying, roto and rotopaint, 2D tracking, multi-threaded rendering and support for OpenFX plug-ins, OpenEXR, OpenColorIO and OpenImageIO. Available for Windows, macOS and Linux. (Licence: GPL-2.0)