Mana rocks can sometimes become irrelevant later in the game when you have a higher land count, so having a rock with utility is great
Alchemist's Gambit is another Crimson Vow card with cleave, and it reads: "Take an extra turn after this one
Fellwar Stone is an excellent signet thats no different from Arcane Signet in the majority of multiplayer games
This time, though, Shalai and Hallar can be your commander, which means you only need to find one other card, usually something White that has scary words like "whenever" and not "this only triggers once per turn." White has a lot of ways to gain life, which puts counters on things, which triggers things that happen when things get counters put on them, which deals damage and then it loops until they get big mad that they lost to a topdecked Ajani's Pridemate and stop coming to your house
Baleful Mastery Why not have your spot removal slots also contribute to the making opponents draw cards game plan with Baleful Mastery
The whole cycle of these flip planeswalkers is hard to evaluate, but Tamiyo looks to be the best of them