Oracle of the Alpha is a reprint of an MTG Arena card from the Alchemy format that was originally digital-only, showing up in paper Magic for the first time
Still, the developers have announced a planned reworking of these systems in the future, and there's already been some modification and alterations made around the edges to smooth out the process in response to the frustrations of the PTCGP community
Since most of these monsters are part of an evolutionary line, fans can likely expect their pre-evolutions/evolutions to also appear
Riku of Many Modes From what I can see, Riku of Many Paths has a relatively low ceiling because he wants you to play with a narrow range of spells and the payoff you get isn't spectacular
and Cronos de Medici to Vellian Crowler, which has a meaner connotation
Like Force of Vigor, it is very efficient at doing what it does, and represents a two-for-one for a single mana