darktable
Description: darktable is an open source photography workflow application and raw developer. It manages your digital negatives in a database, lets you view them through a zoomable lighttable, and enables you to develop raw images and enhance them.
Type: software
Pricing: Free
Skencil
Description: Skencil is a free and open source vector graphics editor for Linux and Unix-like systems. It allows users to create illustrations, diagrams, graphs, and other images using vector drawing tools and has support for layers, gradients, pattern fills, text, and bezier curves.
Type: software
Pricing: Open Source