An app where you can have 2 life counter one for mtg and the second for ygo!
MTG: Tap up to gain life and dawn to deal damage.
YGO: Press "change life points" and insert the number and the math symbol.
You can also have a system of cointoss and dice roll to use in the game.
You can change your default life points and default dice faces.
For ygo part you can have a damage calculator for the battle.