Glad to see I already run half of these in my karlov deck but there are a couple I will now be looking out for. As extra protection for my board state I run an "Athreos God of Passage" and "Righteous war" as well as some other removal
ring of thune seems like a straight downgrade from fountain of renewal, nyx fleece ram or any other gain 1 life at your upkeep ability, also sun droplet. gaining a life will have a better effect for karlov and will synergize better with the rest of the deck