Accel Heroes (加速戦士;Akuseru Hiirou) are a family which debuted as Campaign Promos in BS37. The initial three spirits are themed as Sentai-ish characters, paying homage to the Tiger, Rooster and Monkey God-Kings. All three also possess the family Ten Crown and the same deck-searching effect, however, Gale-Green and Revol-Red have effects which are boosted according to the amount of differently-named Accel Heroes, while Yellow-Merlin's other effect is a life-protecting one.
While the Furigana reads Accel Hero, the kanji is written as Acceleration Warrior. It is worth noting that their flavor text makes a reference to the colors of a traffic light, which might be a gag with how they're accelerating.