Since you'll be casting Dragons repeatedly, the best kinds for a deck like this are ones with powerful enter the battlefield effects, like Thunder Dragon
I think this will work well if you have Setessan Training to give it trample
Through the years, there have been countless ways to turn lands into creatures, but this always came at the risk of losing your mana sources
It's currently easier to find Pokmon cards at Target, but the hobby typically undergoes a seasonal summer slump
Three mana is the sweet spot here, and casting this in your first main to see if it resolves before firing off Day of Judgment is a great play
The second ability can draw cards at the same rate we experienced from Cryptbreaker in Standard not long ago, and this the is the ability that will make or break Kumena as it needs to be very good for multiple Kumenas to see play in U/G Merfolk