the combination I will always check: milf, incest, big ass
tags that I won't even click to see what it's about: female protag, rpg maker, loli, ntr.
one of the worst combinations is fem protag + male protag, which just means the writer has no idea what he's doing and jumps between viewpoints randomly. another one that's not a tag but similar, is games with a girl's name in title. that's just an instant hard pass. also if I see an underaged 'little sister' in previews I never come back. don't care if the game claims they're 18, we all know what child's proportions look like.
basically all these revolve around me liking women with a woman's body and not children, with a power exchange of the less powerful (usually young guy) overcoming the obstacle of romancing or dominating the more powerful mature love interest that's out of his league. unattainable. most mom+son scenarios fit this perfectly so that's what I go for. on sites where 'mom+son' is a tag that's the only one I even bother with.