Of free open sources and free lites: Krita, MyPaint, Inkscape, Gimp, PaintNet, Daz Studio, Natron, LMMS, Opentoonz, Tupi 2D Magic, Hitfilm 4 Express, OBS, PureRef, etc.
Of paid & affordables: Artrage, Rebelle Watercolor, Affinity Designer, Moho Pro, Crazy Animator, etc.
I use many of above alongside Blender.