What an amazing deck, @Bassospades! Feels really unique and powerful.

However, while playing it I've noticed a combo that I'm not sure how to resolve properly. Say, I have Karn, Silver Golem, Voltaic Construct, and Tawnos's Coffin on the battlefield together with infinite mana. Next, I make the coffin a creature with Karn, use Tawnos's Coffin's ability on a creature and while it's resolving I untap the coffin with Voltaic Construct and target another creature. I know that after the abilities have been resolved both creatures get exiled, but when Tawnos's Coffin untaps again, will both creatures return to the battlefield, or only the last exiled creature?

Given any thought to Skyship Weatherlight over Planar Portal? Saves 4 mana and doesn't have any risk if you use it for single search on the turn you combo.

Big fan of the Nim Deathmantle combo, there are at least 3 other options but I never thought of using the worm, bonus worms is a fun perk. My favorite was Su-Chi, when you run lands matter you can get a couple sacrifice artifact /creature lands and use him as burst mana when you need it. If the sole goal is combo, I'd suggest giving him a whirl.

No Walking Ballista? You've got the mana combos and the search, everything else practically ends the game but this guy makes sure everything is dead and torches the corpses for good measure haha