Synfig Studio (App)
Synfig Studio is an open source 2D animation app that can be used to produce both vector-based cut-out animation and film-quality animation using bitmap artwork.
Posted in2D Art Resource Free Drawing App Open Source
Inkscape (App)
Inkscape is a free and open source vector art editor that uses Scalable Vector Graphics (SVG), allowing your artwork to be scaled to any size without losing quality.