Overlord of the Hauntwoods Overlord of the Hauntwoods offers you a big body and instant 5-color fixing through the token land it produces
Make sure your opponents dont have unlimited hand sizes from cards like Reliquary Tower
As for the X spells themselves, that includes a rich variety of Hydras such as Hydroid Krasis, which is overwhelmingly strong even without Zaxara there to generate additional value on the side, along with other staple Hydras like Lifeblood Hydra, Protean Hydra, and the mighty Genesis Hydra
Soldiers was a clear worst, without a real reason to play the type outside of the generic payoffs
Granting haste to all creatures and increasing the mana produced by basic lands can lead to very fast turns, but those benefits apply to everyone, not just you
That makes Fabled Passage is a solid way to fix your mana