Every game (give or take a handful of titles) was released to "the scene" on c64/st/amiga/megadrive/snes etc. during the 80s/90s - the difference with Amiga, it seems to me, is that there were far more trainermakers (specialists, who concentrated on training games) compared with other systems - most games on other systems that were trained, were trained by the cracker himself. I'm not really aware of any guys on most of the other platforms mentioned, who could compete with the likes of Skol/Groo/Ice/Logo 7 etc. on Amiga during its prime.
Of course, a tip of the hat to Pan+TWK/ATX for their great work on SNES, the other exception to my rule