Automated Artificer

The colorless mana this taps for is fenced off by purpose: it pays only for artifact spells and activated abilities, and that restriction is the whole reason to run it over a generic rock. The lane is narrower than it first reads but wider than the flavor suggests. That mana can cast artifact creatures and artifact spells, cover Equipment activations, and feed the activated cost of nearly any permanent you control: a Cycling ability, an Unearth cost, cracking a Clue or a Food. What it cannot do is get spent casting a nonartifact spell, so it never leaks onto the wrong half of a deck. Putting the effect on a creature rather than an inert rock is the real design decision. A 1/3 body can chump, hold Equipment, and register for any effect that counts creatures, none of which a bare mana rock offers; the three toughness makes it a durable early blocker while the ability keeps working. What it will not do well is crew: Crew is paid with power, and one power clears almost nothing worth pointing it at. The trade for the extra utility is a specific kind of exposure: as an artifact creature it answers to sweepers pointed at creatures and to those pointed at artifacts, so it dies to a wider set of board wipes than either a pure rock or a pure body would. This is deliberately hemmed-in ramp, built for a deck that already knows exactly which activated costs and artifact spells it wants that colorless mana pouring into.