I had a ton of game for the Game Boy (plus GBA and GBC) loaded but had paired them down to just my favorites, but I added in tons again to try new ones.
I think ultimately I'll just make two swappable SD cards, one with favorites and one fully loaded with every ROM I can find.
(I'll just keep them both in the travel case I use.)
This will allow a "fun/play" mode and an "explore" mode by just a card swap.