Fellwar Stone

It can add artifact density and fix colors, but a two-mana rock with no immediate mana is far below Modern's usual efficiency bar.

Could be wrong if A proven artifact shell that specifically values both colored fixing and a cheap permanent could make it a niche inclusion.

Legacy's fast mana and cheap interaction make a two-mana, summoning-sick fixer too slow absent a highly specific artifact payoff.

Could be wrong if An artifact prison or color-intensive Ancient Tomb shell could find a narrow use not visible in the supplied context.

It provides artifact count and color conversion, but unlike Ichor Wellspring it does not replace itself and is slow for Pauper mana development.

Could be wrong if If multicolor artifact or Gates lists need durable fixing more than card flow, adoption could exceed this niche estimate.

Existing data puts Fellwar Stone in 35.8% of decks; multiplayer opponents usually make it an efficient two-mana color-fixing rock.

Could be wrong if Its output depends on opponents' lands, so it is less dependable than Arcane Signet in constrained color requirements.

A two-mana fixer can enable splashes, but it neither affects the board nor produces mana on its casting turn, making it conditional filler.

Could be wrong if Unknown fixing, speed, and multicolor payoffs could make splash support either much more important or nearly unnecessary.