effect must be challenging, as the spell needs to be strong enough to carry the remainder of the game on its own, but not so busted as to be easily abused
In keeping with the "tax your opponents' draws" theme, Psychosis Crawler and Scrawling Crawler both deal insane amounts of damage in a wheel deck, turning repeatable effects like Jace' Archivist from a nuisance into an actual threat
In addition to this, OP04-112-Yamato and OP04-104-sanji would also be important upgrades for this deck (and quite useful for the yellow color in general) and they are less expensive than the aforementioned, and you could start here
The List: Best Ruby Cards in Fabled 1) Mickey Mouse - Brave Little Prince (Iconic) What it does : Cost 3, Ruby Character, Shift 5, Evasive
Gruul Azorius -- That's this article
What Happens If I Blink an Additional Land Card