As some have pointed out: There's always the question of how many special and elaborate tricks you're willing to apply and whether you'd still consider all that actual "support" for a game by the same machine.
I mean, where's the clear border to "use you modern machine and DOSbox", eventually.
Or, whether at some point you'd go "let's acquire a dedicated 286 for some games because it's less trouble".
If you do, maybe the sweet spot may rather be a 386 with a turbo switch. Pretty sure those are easier to source and set up.
(And then you could consider somewhat maxing out the socket 7 with a faster CPU)
Example dear to my heart: You haven't seen the golden age of DOS gaming if you haven't played the original X-COM or "UFO - Enemy Unknown" from 1994.
For the authentic experience with the essential, time-honored bugs, you'll need the DOS floppy version.
That will feel just fine on a 386. Scroll speed on the tactical screen is the key.
(the close successor, "Terror from the deep" will already give you trouble with slower ISA VGA)
And I think I've played it on a P133 as well.
The list on vogonswiki says p90, maximum.
So, with that range of games:
- Maybe clock the machine down to 1.5 x 50 MHz FSB. It's possible to attach front-mounted switches to jumper headers, if you want to tinker.
With UFO, the cheap way out is the "Gold" edition for Windows... That should be right at home on a p133. Then, very much the same problem on, I'd say, anything past a GHz.