1 Tuner + 1 or more non-Tuner monsters You can remove from play all "Iron Chain" monsters from your Graveyard to have this card gain 200 ATK for each card removed, until the End Phase. When this card inflicts Battle Damage to your opponent, send the top 3 cards of your opponent's Deck to the Graveyard.
Here are the monsters you can banish from your graveyard to boost Iron Chain Dragon’s attack. Iron Chain Coil can even help your Iron Chain Dragon gain stats as long as Iron Chain Coil remains on the field.
It's a generic Level 6 Synchro with decent ATK, you can use this in any deck, since the effect that uses "Iron Chain" monster is not mandatory and just a temporary ATK boosting effect anyway, which can be done using other cards.