I went down some Covid quest of lunacy where I made literally hundreds of genesis cartridges. Yes, I’m aware of and own everdrives and multicarts, too. Got very intimately familiar with those pcbs by the end of it.
Just to have a pile of them to run my fingers down while picking one to play. I started with a small list and then recreated my childhood. Then it was all those “always wanted to play that” games and the finally modern homebrew.