Many entries in the Sega Ages 2500 Series were designed to be compact. Titles like Golden Axe (149MB uncompressed) can be shrunk significantly further using modern tools.
When searching for on Google, you are entering a digital swamp. Here is what to avoid: Ps2 Games Highly Compressed Under 50mb
To get a game from 2GB down to 50MB, "rippers" perform several steps: Many entries in the Sega Ages 2500 Series