IMO, it's hard to claim best game of all time unless it ages well, and not just some unique gimmick the game provided at the time.
Ie, I don't like Tetris but for sure it is one of the best game of all time.
However, if what you mean is good games that somewhat get outshined by others or lacks media attentions, then I agree. There are plenty of other games, and I think people would have bias toward their favorite genre/type.
that's why I argue you can't put "best" and "all time" together. If the title says "best game of their time but got snubbed by medias" then I might have a couple of my own to provide as example.