Krita, the open source painting program has a LOT of users. The interface has improved greatly over the past 5 years. To the point where it rivals other software for painting.

• Krita Learn - https://docs.krita.org/en/
• Krita official youtube - https://www.youtube.com/c/KritaOrgPainting/videos

• 5.0 improvements and stability - https://www.youtube.com/watch?v=jE02xGd2CCY
• Krita 5 in 5 minutes - https://www.youtube.com/watch?v=uajURZG9WCY
• Krita 5 RGBA wet brushes
• easy theme changes - settings > theme
• quick access menu (right click on canvas)
• Python Scripting - https://www.youtube.com/watch?v=uNEQ5t6YhKU
• Open Source
• Great commuity
• Active development
• Many many tutorials online
• 3D transform
• Mesh Transform
• Animation tools with timeline!
• Vector capabilities - https://www.youtube.com/watch?v=YVe8Lt43mUs
• Some g'mic filters are in Krita NOT in gimp. what?
• MyPaint Brush support - slow but nice
• Can export a recorded movie of your drawing process - wow!
• Python Scripting in Krita doc

• Layer Export - https://github.com/GDQuest/krita-batch-exporter
• G'Mic -
• Brush packs out the wazoo
• Subwindow Organizer
• Photobash plugin - https://github.com/veryprofessionaldodo/Krita-Photobash-Images-Plugin
• Random lineart color trick G'Mic plugin - https://www.youtube.com/watch?v=Bvi7p3sRIJM
• Rakurri Brush Set - https://rakurri.gumroad.com/l/rakurribrushes1
• David Revoy's Brush Kits - https://www.davidrevoy.com/tag/brush
• watercolor brush set (old) - https://github.com/vascoalexander/krita-watercolor-set
• Krita's official resources page - https://docs.krita.org/en/resources_page.html
• Krita artists plugin dev page - https://krita-artists.org/c/develop/plugins-development/16
• Opendesktop / Pling - https://www.pling.com/
• Digital Atleier Brushes - https://www.youtube.com/watch?v=O2wiEYGGc6I

• https://www.youtube.com/watch?v=FvvGXN8WFg0
• UI theming guy - https://www.youtube.com/watch?v=ChF9XWSSDFI&t=309s
• Oil Painting Krita Wet Brushes - https://www.youtube.com/watch?v=cGaVQaFI64k
• Colorize mask feature in Krita - https://www.youtube.com/watch?v=Bvi7p3sRIJM
• top 5 new Krita 5 features - https://www.youtube.com/watch?v=oplI8toSb8w
• Watercolor Brushes - https://www.youtube.com/watch?v=drYOrnG0Ui0
• Customizing Line Art Brush - https://www.youtube.com/watch?v=2PMlGumC10o
• 10 Tricks to Paint Better & Faster in Krita - https://www.youtube.com/watch?v=-LYfXyrGNe4
• Improve Sketches in Krita - https://www.youtube.com/watch?v=HtBzzXulIr0
• Using Public Domain Book Images - https://www.youtube.com/watch?v=g5X95lqdhfE
• Smoother lines in Krita - https://www.youtube.com/watch?v=CrmcqeoLyag
• How to use Krita's Assistant Tool (circle guides!) - https://www.youtube.com/watch?v=Z6VRaVkrEII
• Drawing Architecture with Assistant Tool in krita - https://www.youtube.com/watch?v=1ThLDN5My_s
• screentone & halftone patterns in Krita - https://www.youtube.com/watch?v=vWHeUlipSmo
• Warp and transform - https://www.youtube.com/watch?v=TQ8iIQU9KHc