X #6 Visualize the distrbution of grades in the chart
The second attack for Gengar V is Pain Explosion, which deals 190 damage
You can add in hexproof creatures and play a Voltron- / Bogles-style deck, head toward enchantment creatures like Courser of Kruphix with Kestia, the Cultivator leading the way, or go all-in on comboing off with Estrid, the Masked and The Chain Veil
The M Charizard ex was the first card in the game to have a base attack damage of 300 and remains one of the strongest single-card attacks
You'll probably need some secret packs and card crafting to flesh your collection out, and make sure cross-save is enabled so you don't lose all your progress if you switch platforms.
"Obelisk" would have been able to destroy "Slifer" with its effect during Yami Yugi and Seto Kaiba's Battle City Duel if "Slifer"'s ATK hadn't been over 4000 at that time