There were multiple revisions, Beta contained about 100 different cards, and as far as I've learned, there were no Chaos Orb / Sphere of Annihiliation versions in Beta
Originally, the Reserved List promised not to reprint any cards from Alpha or Beta , any uncommons or rares from Arabian Nights and Antiquities , or any rares from Legends or The Dark that had not already been reprinted in white border (in the early days of Magic , white borders were used to represent reprints)
Going off of feel alone, Id guess youll get something useful about half the time on turn three
When it enters play, you get the awesome upside of gaining 20 life
Outside of removal, there's other powerful spells like the game-ender Exsanguinate, and the value engine Lingering Souls, both of which work well with Y'shtola's abilities due to being greater than mana value 3 when cast
To add to this: the pokedex order is superceded by evolution lines if they are within the same type