I have a mike piazza rookie o the year card topps, and a 86 topps nolan ryan. Have several but those always pop in my head first. Do they have any value now or in the future will they become valuable? They are in mint condition

I've got a lot of cards and when I'm curious, the first place I check is eBay... and if I find the card that I've got I put it on my watch list to see what it sells for. I've yet to find an online value guide, so if you're near a bookstore or library, look them up in Beckett's to get a ballpark of the value if they're not on eBay.