Like previous Commander releases, all of Commander 2019s decks were designed around a central theme, and this year that theme is Mechanics
Mana Vault left Extended just in time, but don't underestimate the importance of the drawbacks of Vault against Monolith - you have to untap it on your upkeep, and it does damage if you don't
They have no drawbacks and count as both lands making them ideal for fetching and land searching that cares about land type
Ive written a lot about the foil extended art cards only available in the Sample Packs, and unless youre buying in significantly below TCG or Ebays listed prices, I cant tell you to buy these for long-term growth
Blood Artist is probably a first choice
What are the most powerful characters, and which are the rarest