Hi Fenix,You could always download Atari St game roms from emulatore sites and transfer them back to disk to play on the ST but you will have to explore the different ways to transferring them back to disk it is not straight forward as it sounds but once you have managed one them the rest should be a doddle:)
What i have done is format a disk on the ST then take it to the pc and pop it in the just transfer the downloaded rom to the disk and when finished take the disk to the ST and load.The only snag is if the ST game rom is bigger than 720k and it says 880k then thats when it gets weird because you have to use another program to format the disk on the ST to 880k then you can transfer a rom to that disk???? Have a go at a simple 720k rom and you will be suprised:) Enjoy all those free Atari ST games :))))))))