At 4 mana it would have been really good
Cumulative upkeep 1 (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) When Ancestral Knowledge enters the battlefield, look at the top ten cards of your library, then exile any number of them and put the rest back on top of your library in any order
If one of those creatures has one or more variants of the listed keywords (for example, islandwalk), creatures you control gain those specific variants
I've also seen people just toss in commons and think it's budget when many commons are more expensive than bulk rares
For more information on where to find these cards, read our guide to Collecting Magic: The Gathering | Teenage Mutant Ninja Turtles
With Oswalds Favorable Chance ability, every time you put a card in your inkwell you can choose to reveal the top card of your deck