In the old days, a D&D DM rolled up a treasure based on the treasure type of the monsters in a location. Each treasure type had a percentage chance for various coins, gems, and magic items. Blog of Holding did a good review of each D&D edition’s treasure determination method. More recent editions have streamlined treasure determination but also made them largely identical.

The beauty of the old tables–before 3e–is that the same treasure type can yield substantially different treasures depending on the rolls. If you make those rolls in front of the players–or let the players roll–it feels more exciting, like gambling. They might catch a big score or get very little.

Now, there’s probably too much treasure given out by these old tables. Those systems assumed characters were saving up to build a stronghold, but few care about such things now (altho WotC wrote an optimistic “bastion” system into the 2024 books).

I would suggest, therefore, that you create your own table with smaller treasures, but you should maintain the randomness, so that there’s no telling what treasure might be found. I’ve created my own treasure type system here.