>>52341197The mainline games do absolutely nothing with them, but I love how they represent a sort of ancient wild magic that have long since outlived their original purpose and creators, if they even were created. The TCG does interesting things with them, namely unown cards can have some weird gimmick that's very powerful, but very inconsistent, like immediately winning the game if you have 35 cards in your hand. I also like the flavor that unowns power grows and changes depending on the number of unown and the words they spell.