Q-Bert (Pipe Dream Interactive/Hasbro Interactive, 2000)
It's Q-Bert. It has an "Adventure" mode, but it's not clear what makes it any different than the regular game. Not that I played much of it, because I've seen enough of this game for one life.
Qix Adventure (Taito, 1999)
Taito arcade games are usually pretty good, but this isn't. You need to draw lines to claim 75% of the play space. That'd be fine, except your cursor moves ridiculously slowly, you're on a timer, and this stupid Windows screen saver of death randomly jumps around the middle third of the screen constantly.
Quest: Brian's Journey (Atelier Double/Sunsoft, 2000)
This game is not as bad as Powerpuff Girls, but it is an RPG with awful music, writing that comes straight from a "Learn English in 15 Minutes a Day" CD, and extremely indistinct character sprites. I didn't see much of it, because on top of all that it also likes large spaces and very slow movement speeds.
Quest: Fantasy Challenge (Imagineer/Sunsoft, 1999)
It's basically Dig-Dug except that your attack instantly kills whatever it hits, but then you can't attack again for a solid 15 seconds. It mostly involves being chased around in circles by enemies until your attack turns back on, and then hoping they back off enough for you to use it.
Quest for Camelot (Titus Interactive, 1998)
A Zelda-like based on a long-forgotten animated movie. I had it as a kid and remember it being pretty decent, but I can't confirm that because the very slow, unskippable, and completely silent intro took up most of the time I had for it. That means it's going on the list.
Qui Qui (Mahou, 1999)
You're raising a bunch of these rabbit things in a game that doesn't look like a Tamagotchi knockoff at first, but then totally is.
Racin Ratz (KnowWonder/Mattel, 2000)
Actually more of a puzzle game where you're trying to get your RC car to the end of an obstacle course by using various powerups and whatnot you find along the way. You can't use anything in the wrong place, so it's not a very difficulty puzzle, but it's not at all a racing game.
Rainbow Islands (Taito/TDK Interactive, 2001)
You can climb up the wall of islands by spawning little rainbows that you character can walk on like a staircase. If a rainbow hits an enemy, they die. A straightforward arcade game that has the Bubble Bobble music for some reason.