• Making a first gif with Processing
• Loop from periodic function and offset (Processing)
• Noise propagation (Processing)
• Replacement technique (Processing)
• Replacement technique with 2D grid of objects (Processing)
• Motion blur template (by beesandbombs) (Processing)
• Drawing on a path computed by steps (Processing)

Note : I’m not explaining the basics of drawing with Processing. This is focused on gif/loop techniques, assuming you already know how to draw with Processing or similar framework. Those tutorials are about general loop techniques and it can actually be better to avoid those techniques to find more creative loop ideas.