For me I guess it depends how exactly we define DOS game. If we mean games where DOS was the initial or primary release platform, then I think only DOOM would make my cut of best games ever. If we include anything that merely had a DOS version, then Lemmings would be in there too.
I think the reason so few games make the cut for me is also the reason the platform is so interesting. It was a highly experimental wild-west where new and strange things were constantly being tried, many of which either didn’t work, or needed further refinements to really shine. Console games tended more to focus on established formulas and iteratively refining them, which is why the “best of the best” exemplars tend to be found there.
EDIT: And just to clarify, I interpreted this more in an objective “what games achieve the highest quality” sense, rather than just a list of my favorite games. Many of my favorite games are deeply flawed in some way, and several more DOS games would be included in that case, such as Descent, Hexen, many Sierra adventures, etc.
