Two tools stand out in particular: BigJPG and AI Image Enlarger, both of which are free and easy to use. BigJPG is a practical tool that is available both in the browser and as a Windows application.

Video, Image and GIF upscale/enlarge(Super-Resolution) and Video frame interpolation. Achieved with Waifu2x, Real-ESRGAN, Real-CUGAN, RTX Video Super Resolution VSR ...