Budokan: the Martial Spirit (I just played this yesterday albeit on DOSBOX and it really brought me back to the days I used to play it on my friends 286)
Scorched Earth (original)
Civilization (as PeterLI mentioned above)
SimCity (original) as Donutking mentioned as well, but I just wanted to add that I think this was one game that took advantage of a Co-processor (if your 286 can take one)
Leisure Suit Larry 1 and 2 (and I think 3 ran good on a 286 as well) and pretty much all Sierra games before King's Quest V came out I believe were some of the best games to come out during the 286 era.
The original Links golf game (if you're into that sort of thing)