Okay, this is going to be problematic. I do want to give Phenax some synergies, but I don’t want to make him too powerful. That ability in limited is just too strong. So, what I’m thinking is no walls, and maybe try to encourage milling yourself.
Phenax’s Two-Colored Cards
First, [scryfall]Architects of Will[/scryfall], with the point being that you can check whether you want to mill your opponent, or yourself. You can also always cycle it cheaply, if it feels bad in the moment.
[scryfall]Dimir Charm[/scryfall]’s third mode is something that works very well here. Its on the same theme, but you get some control over what you are putting into the graveyard.
[scryfall]Dimir Doppelganger[/scryfall] seems fine, as well. It gets a full benefit from milling, if nothing else.
[scryfall]Dralnu, Lich Lord[/scryfall] is tempting… But no.
[scryfall]Havengul Lich[/scryfall] is better. Probably in. There isn’t much room here, but I like it.
If we have enough flashback, delve and recursion, maybe [scryfall]Unfulfilled Desires[/scryfall]. It was part of a very powerful combo deck back in the day, but here it could be a great enabler.
[scryfall]Possessed Skaab[/scryfall] is worth putting some thought into. Its pretty expensive, but its also powerful. The body isn’t meaningless and if you have enough stuff in your graveyard, you’ll definitely get good value out of it.
[scryfall]Soul Manipulation[/scryfall] is on the other end of the spectrum, as it seems too powerful.
[scryfall]Forbidden Alchemy[/scryfall] seems like a good idea. It encourages self-milling, if nothing else. [scryfall]Mystical Teachings[/scryfall] does the same and it works well with the Faerie subtheme.
I’ve always liked [scryfall]Extract from Darkness[/scryfall], although I also know its not going to be very good in this cube, most of the time. It feels like a sideboard card.
[scryfall]Fathom Feeder[/scryfall] is one of my favorite cards from BfZ and would sort of work here. You can’t get stuff into the graveyard with it, but you can sort of use it with cards like [scryfall]Dewdrop Spy[/scryfall] I already put into the cube.
[scryfall]Cavern Harpy[/scryfall] isn’t really one of the cards you want for this specific deck, but since I’ve injected a Faerie theme and this works well with that theme, I’m putting it in anyway. Again, we don’t need to try to make Phenax better. We need to try to make him more interesting.
I’m going with this selection:
We are looking for ways to either mill ourselves, or ways to encourage that.
[scryfall]Dakra Mystic[/scryfall] is subtly powerful, especially here, if you are dropping a card which you don’t mind discarding, because you can use it from your graveyard, or you are fueling your delve.
Another graveyard enabler would be [scryfall]Deranged Assistant[/scryfall]. Extra mana isn’t bad either.
Some more flashback would be nice too: [scryfall]Think Twice[/scryfall] and [scryfall]Deep Analysis[/scryfall]. Also, [scryfall]Runic Repetition[/scryfall], although I doubt it will remain here very long. I just want to test it out. The problem is that you don’t necessarily want those cards anymore, because they aren’t usually that effective.
[scryfall]Day’s Undoing[/scryfall] can enable the graveyard and it seems like a fun, if pretty unusable card.
[scryfall]Archaeomancer[/scryfall] and [scryfall]Treasure Cruise[/scryfall] are payoff for getting stuff into your graveyard.
Again, some Flashback and some Delve. Actually, maybe too much delve, but we’ll see. I didn’t put any Dredge cards here, because there’ll be some in Pharika edition and those two decks can compete over those cards.
Also, [scryfall]Bloodsoaked Champion[/scryfall] which can recur itself and [scryfall]Puppeteer Clique[/scryfall] which can abuse the graveyard from a different angle.