Not sure what your budget is, but other handy lands include Reflecting Pool, Field of the Dead (if you can swap out some lands for snow lands), Mana Confluence, Temple of the False God, the Fetches on-color (or even Prismatic Vista or Fabled Passage if you're basic-heavy)
Thats just my experience, but having tried out several of the different Avatar prerelease kits on Arena (there are five in total), Im definitely most impressed with what black has to offer
12 November 1999
Ariados can be obtained from Wisdom of Sea and Sky: Ho-Oh pack in the Wisdom of Sea and Sky set
You can also use flicker or bounce effects like from Legion's Initiative, which is in red, allowing you to trigger an additional four damage while giving it haste to trigger another four in combat with just two mana
So if youre not overloading your opponent with them, theres virtually no way something like Thing in the Ice or Jace, Vryns Prodigy or any other cheap creature is going to survive if its your only target