Hermitic Herbalist

Read the second tap ability twice, because it is where the deckbuilding decision actually sits. A garden-variety mana elf fixes for anything, once per turn, and this creature offers exactly that as its first option: one mana of any color, no strings. The second tap doubles the output but fences it off entirely, spendable only on Lesson spells. That restriction is what makes the rate payable at all: two mana of any colors on a two-drop would be broken as generic ramp, but the "Lesson spells only" clause means you cannot funnel it into a creature, a removal spell, or anything you want to interact with on the stack. It feeds one subsystem and no other. That is the design discipline working: the card accelerates a Learn/Lesson engine without becoming color fixing that any two-color midrange deck would run for the mana alone. It is a build-around dressed as a staple, and the split between the two tap abilities is where the choice actually lands. The 2/3 body is the insurance policy: once the Lesson well runs dry, the flexible single-mana half keeps the card doing honest work rather than rotting in play, so the fixing mode never becomes dead weight after the engine has spent itself.