TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
ImageOptim - Faster web pages and apps.
TruePNG - Command-line PNG optimizer.
Oxipng - Oxipng is a multithreaded lossless PNG compression optimizer. It can be used via a command-line interface or as a library in other Rust programs.
pngCrushrrr - Drag your PNGs onto PNGCrushrrr and get super-optimized files ready to be emailed or posted on the...
pngquant - command-line utility and library for lossy compression of PNG images