I find the topic title to be misleading, it made me expect to open a list of games that can be played without DRM and I myself see a disc-check as being DRM. I find it a great hassle to switch disc each time I play the game plus disc-checks often make use of the method of adding bad sectors to the disc, the disc-drive has trouble reading, but the DRM checks for it, like the old SecuROM did, causing disc-drives to wear down much faster than it would have otherwise, reducing it's lifespan immensely. In the old days of discs, it was always the drive which was to break down first on older computers of mine.
So a list of DRM-free retail games for me would include games like:
Brothers in Arms - Hells Highway: installed from disc, but doesn't make an internet connection phoning home and the disc needs not to be inserted for playing.