Yes, both ImageOptim API and LibPixel offer a Free Trial.
ImageOptim API is designed for Large Enterprises, Medium Business and Small Business.
LibPixel is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Pricing for ImageOptim API Starts at $12/Month whereas for LibPixel Starts at $15/Month.
Some top alternatives to ImageOptim API includes Resizing.app, Cloudimage.io, Imagekit.io, Imagify, imgix, image4io, EWWW Image, TinyIMG, ShortPixel Google Drive Optimizer, OptimizeImages and ImageBoss.
Some top alternatives to LibPixel includes Resizing.app, Pixelz, Resizer, Cloudimage.io, ShortPixel, ShortPixel Google Drive Optimizer, Pixelied Convert, ImageBoss, Qualified, Workvivo, Pixelshift.io and IFTTT.