Expedite

Haste as a cantrip is the design idea here, and the implications run deeper than the effect suggests. Most haste-granting spells ask you to pay for the keyword and accept the card disadvantage as the price of surprise. This one refunds the card immediately, which means the haste is closer to free than it looks: you're spending a single red mana and a card slot, then getting the slot back. That changes what the card is for. It stops being a tempo gamble and starts being a sequencing tool, a way to push a freshly cast threat into the red zone the turn it lands without spending net resources to do it. The cantrip also quietly enables uses the haste alone never would: chaining it through a creature you control to sift one card deeper, smoothing draws while incidentally arming a beater. Granting haste to a creature you cast this turn is the obvious line, but the more interesting one is using Expedite as a one-mana red filtering spell that happens to staple a combat-relevant keyword onto whatever's already on the board. It is a small effect built so the deck never has to feel the cost of including it, which is a harder design problem than it appears and the reason cards like this keep getting reprinted long after flashier haste enablers are forgotten.