Most of them I would assume. Everything from 2006 forward started to use Xinput. DirectInput support only shows up in racing sims, flight simulators, fighting games and emulation. But all the big AAA games have been built around Xbox360 style control schemes for two decades.

But it's all a bit theoretical, since most modern gamepads have Xinput support, and the generic HID devices are mostly flightsticks or SNES-style gamepads that wouldn't have enough buttons and axis for modern games in the first place. Another issue is that most games don't offer input remapping for gamepads.

But with SteamInput and homebrew tools like x360ce there are many ways to make generic USB devices compatible Xinput, so it's not like you can't use them. It's just not something that works out of the box.

That may explain it then. I use flight controllers and driving controllers. Both just show up as generic HID devices and both are easily used in the games I play.