(Don't forget to write the Materials.)
Mechanical Comet Dragon
This card gains 100 ATK and DEF for each Union monster and Equip Spell in your Graveyard. Unaffected by your opponent's card effects while there is a face-up Equip Card on the field. Once per turn: You can reveal 3 Equip Spell Cards and/or Union monsters from your Deck, add 1 of them to your hand, and shuffle the rest back into the Deck. When an opponent's monster declares an attack: You can target the attacking monster; banish this card, and if you do, negate that attack. During the next End Phase: Special Summon this card banished by this effect.
Gaea the Stone Monarch
EARTH Warrior / Synchro / Effect
2800 / 1000
1 Tuner + 1 or more Tribute Summoned non-Tuner monsters
Must be Synchro Summoned, and cannot be Summoned by other ways. You can Special Summon this card (from your graveyard) by sending the above Materials to the graveyard while you have no cards in your Extra Deck (this is treated as a Synchro Summon). When you Tribute Summon a monster, you can target one face-down Spell/Trap Card on your opponent's field: Banish it, then if it was a monster, your opponent takes damage equal to its Level x 200.
(Since some monster cards, like Artifacts, can Set themselves in the S/T Zone)
1 or more Pendulum Tuner(s) + 1 Level 4 "D/D" monster