Like most Magic: The Gathering cards, the value of Aerith Gainsborough depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Pro Tour Promos)
Bloodghast can get milled, then come back onto the battlefield each time Landfall is triggred (which is easy with fetchlands)
Creature Artifact - Golem Color tag templates(None) Stitcher's Supplier When this creature enters or dies, mill three cards
Youll need enablers for the latter, but its got a lot of potential
Look for high-rarity cards that synergize with your pieces rather than standalone cards that are an obvious threat
(There is psychological value to countering an opposing spell with a Force Spike since they are so easy to play around, yet it's not worth playing around them in Commander because they aren't heavily played, which makes getting your powerful spell hit by Jwari Disruption especially devastating.) As for the rest of the bunch, Silundi Vision is listed as an often play just because you need to be a reasonably spell-heavy deck for it to work