Gimmick deck designed to get 12
Lumen Reclaimer with all (16) skills and to check for deck limit.
This deck has the potential to hit the "free card limit per turn" (50 cards) relatively easily by stringing together Echo/Destiny copies of Lumen Reclaimer. With this, the deck at the end of the game contained 830 cards (approximately 750 of which were Lumen Reclaimer) with 12 Lumen on the board and one card in hand (deck card limit still unknown).
I have to hand it to the developers because I was able to see the order for every card drawn and the full deck at the end of the game in the match history, but it did load very slowly.
Edit: End of game deck was at 1382 in the previous game, which implies there is no hard deck limit.