Have you have ever heard of Krita?
Krita is a professional FREE and gratis software painting program. It is made by artists that want to see affordable art tools for everyone.
What not everybody knows, is that Krita originates from Calligra, a KDE project.
Calligra Suite is an office and graphic art suite by KDE. It contains applications for word processing, spreadsheets, presentation, vector graphics, and editing databases.
You can find Krita here:
https://krita.org/en