While 50 MB is unrealistic for AAA titles, there is a niche library of PS2 games that are naturally small and can be compressed to under 100 MB (or occasionally under 50 MB) without destroying the experience.
Here is a list of legitimate PS2 games that, when compressed with a high-level 7zip or CHD (Convertible Hard Disk) format, can reach ridiculously small sizes while maintaining "high quality" because they were simple to begin with. ps2 games highly compressed under 50mb high quality
Textures (character faces, environment details) are resized from 512x512 to 32x32. Characters become blocky blobs. Menus become illegible. While 50 MB is unrealistic for AAA titles,
Music and voice files are stripped to a fraction of their original bitrate. Final Fantasy X’s "To Zanarkand" will sound like it’s playing through a telephone from 1985. Sound effects will hiss and pop. Characters become blocky blobs