Adobe After Effects is described as 'Professional-grade motion graphics and visual effects tool for post-production in film, TV, and creative projects through cloud subscription' and is a very popular Motion Graphics software in the photos & graphics category. There are more than 50 alternatives to Adobe After Effects for a variety of platforms, including Windows, Mac, Web-based, Linux and iPhone apps. The best Adobe After Effects alternative is Natron, which is both free and Open Source. Other great apps like Adobe After Effects are Blender, Blackmagic Design Fusion, NUKE and Apple Motion.
Free and open-source node based alternative to After Effects. It's pretty similar to Nuke, but doesn't cost anything.