GIMP

Design Tools
Tools
T Text tool Win mac Linux
G Blend (Gradient) tool Win mac Linux
R Rectangle Select tool Win mac Linux
E Ellipse Select tool Win mac Linux
⇧ Shift+E Eraser tool Win mac Linux
⇧ Shift+P Pencil tool Win mac Linux
⇧ Shift+B Paintbrush tool Win mac Linux
Selection
CTRL+A Select all Win mac Linux
CTRL+⇧ Shift+A Select none (deselect) Win mac Linux
CTRL+I Invert selection Win mac Linux
Editing
CTRL+Z Undo Win mac Linux
CTRL+Y Redo Win mac Linux
CTRL+C Copy Win mac Linux
CTRL+X Cut Win mac Linux
CTRL+V Paste Win mac Linux
View & File
+ Zoom in Win mac Linux
- Zoom out Win mac Linux
CTRL+S Export (overwrite) Win mac Linux
CTRL+⇧ Shift+S Export as new file Win mac Linux