I see you say ‘no resale value’, but specs like that do 650,- to 700,- here in The Netherlands. Are you sure there is no value here? It seems as a firewall, it will consume lots of electricity. (Too much for 24/7?)

Super Mario Advance 1,2,3 and 4

Sinden light gun, as mentioned in this thread

My favorite retro game is Super Mario Land 2: 6 Golden Coins. That is because it was the first game I purchased for the Game Boy after I got tired of Tetris. I played it so many times! I can still remember every level. Good times.