Pixel Pix - Turn your photos into pixel art
Trigraphy - Photo editing app that allows you to make mosaic/abstract looking art.
PictureThat - Fill your walls with art and photos in AR 🎨
Dreamscope - Make and share 'deep dream' images using dozens of supplied styles or your own.
Da Vinci Eye - Learn to draw by using your phone to overlay images for you to trace
Photomosh - Turn anything into a vaporwave