At one point I played predominantly Machines, then I was onto Dragons, then Fiends. I'm circling back to Machines again, and I want to make Machina funtional because the aesthetic for these cards is exactly what I want.
If it weren't so hard for me to get my hands on Psychic Processor would be perfect, but alas. I haven't found myself fond of many extra deck cards yet, I like to play things a bit more pure and there's a lot of push towards the rank 10 trains.
Double Wild can pull Citadel to hand and special summon it, Mound is protection for Citadel and Ruinforce, Infinitrack Tunneller is a monster version of Pot of Avarice, Urgent Schedule and Magnet Force- there's a lot of good options it seems, and Im trying to cut out what isnt needed as much.