Preliminary testing has me enthousiastic about:
These are the only cards I've tested so far, but they've all been excellent. Savage Stomp being a mana cheaper than
Hunt the Weak apparently makes all the difference, and if you get to use it with one of the two excellent dinosaurs (caveat,
Flame Jab was already in my cube before Ixalan was spoiled) you... Well, let's just say I felt giddy the first time I pulled off a kill spell + Rampant Growth for a single green mana
Makeshift Munitions has been a great Goblin Bombardment alternative. A little less abusive, but brilliant with the additional artifacts that can suddenly go face. It has sweet synergy with the unexpectedly awesome
Curse of Opulence!
Chart a Course has been as solid as people have been expected. I've used it to put a fatty in the graveyard while digging for the reanimation spell, and I've used it as a two mana draw two spell. Both are super excellent modes for the mana, definitely going to add this.
Hostage Taker is just such a sweet card, and I don't think I need to explain why
Haven't tested any other cards from Ixalan so far, but I expect Kitesail Freebooter is going to earn a spot at least.
I don't know if I'm going to add any of the flip cards. I think
Vindicate might be the only card that can actually deal with them once flipped (they all turn into lands), and I'm not really keen on introducing must kill lands when I just completely removed all of them from my cube.