Which card should i remove from my deck?

Judging from your cards, I assume you are making a machine/machina deck. If so, you should just stick with 3 machina fortresses, 3 of each gadget and some cards that help you search for machina fortresses. Stick to a deck that focuses on summoning the machina fortresses with cards like majic jammer and mystical space typhoon to protect your guys from spells and traps. Keep your deck to 40 cards and you should have an almost unstoppable deck.