I have to say I legitimately must have played with over a hundred different people. I've been gaming for 30 years, roundabout. I played at a gaming shop for about 2 years, where I may have played with over a dozen or two dozen people, easily. Then for years at home where I probably played with a dozen others, counting family and friends. Then another game shop, where I frequently DMed for 10 or more people and probably altogether gamed with and for several dozen people; some were not DND but it's been long enough that I can't separate out who and when and what. Throw in a couple gaming cons where I probably played with another half-dozen folks, a few years at college with another half-dozen more friends, and then in the past ten years at a third game shop. I've easily played with 15-20 different folks up there and at work and at home in that time...
So I'd say a hundred is a good conservative estimate of people I've played with at DND and possibly a jumble of other games together. But the bulk was DND or a derivative thereof.