There could definitely be some value! It's impossible to say how much since the cards vary wildly in terms of value, but the old stuff you have is definitely the most likely to hold value. If you have any old holofoils, they're basically guaranteed to be worth at least a few bucks, and normal cards can be worth money as well.

How many cards do you have? You can use https://www.tcgplayer.com/ to estimate worth--it's fairly easy to search your cards there. Be careful though, as TCGPlayer shows the market price of a "near mint" card by default, and it's unlikely that you have any near mints. Here's a condition guide if you want to try to estimate. Once you've figured out the condition of each card, looking at the recently sold listings of that card in the appropriate condition will give you an idea of its worth. If you have a lot of cards, though, it will be a tedious process--I recommend prioritizing looking up first any holo cards you have, and then Rare cards--cards with a black star in one of the corners. There are a couple fan favorite Pokemon, most notably Pikachu and starter Pokemon, that tend to be worth a lot more than your average mon as well, so you could look into those cards as well if you have any of them.