I think 90s comics will still have some minor collectability. Like, unless they're the premium stuff not a ton but with the comic movie boom they still hold a bit of sway. I'm thinking the 1990-1992 Impel Marvel and 93-94 Marvel Masterpieces. They're not gonna make you rich but I'll generally grab those if I see them in a $.50 bin just to look at. To get anything much out of those they usually need to grade well but they're still worthwhile.
For 80s sports...it's really rough. Very generally, I'd say if you have time take out cards of your S-Tier players (Hall of Famers or Super Popular Guys - Griffey, Randy Johnson, Mattingly, Bo Jackson, etc.) as those can still pull in a bit of change - also pull out rookies of more notable players. You'll see moving boxes of like 10-20k of these cards go for $15 to people who just want to prune, and it's mostly worthless otherwise. I'd say if you get back before like...1987 or so it may be worth looking more, but cards from 87-92 or so were SO heavily produced that only the cream of the crop tend to hold even minor value and I don't think they ever will. It's probably destined for recycling/trash.