BreOl72: You could filter the games via price.
Especially setting the filter to "under $25" or "$25+" will solve your problem.
Maighstir: Or game features. DLC's didn't have features last I checked. I guess Gwent is multiplayer-only, but pretty much all other games here have single-player, so I'd filter for that.
I was already filtering by price, I was looking for something cheap, which exacerbated the problem, but as a place that I've always used to buy cheap games, I'd really hate to feel like I'm supposed to spend $25 or be made unwelcome.
And the game features thing doesn't help, sadly. It appears all the DLC, soundtracks and artbooks just inherit the features of their parent games. In fact, filtering by "single player" in the example i screenshotted just filtered OUT the games bundle, leaving me with one game on screen!