Iron Valiant ex has a special ability, letting you add two damage counters to any one of your opponents Pokemon
Thunderforce Attack is a new Spell Card that will destroy all your opponents face-up monsters at any time, but if you use it during your own Main Phase you can draw a card for each monster destroyed! That sounds like fun
More recent equipment like Maul of the Skyclaves automatically equips itself to a creature, which helps to take away the sting of equip costs when Ardenn isnt available
Not so much for the card in the actual game, but for Yugi Muto's duel against Weevil Underwood in the anime in which Yugi uses the card against Weevil to draw a bunch of Monsters, which is one of the most savage (and satisfying) overkill moments in
For each starter pack, Mewtwo, Pikachu, and Charizard have certain cards that can only be found in their specific packs