For my unpowered, low curving, synergy
cube, there are a ton of goodies that are likely staples for a long time.
I decided to omit the MDFC lands from the cube, but there are some really strong ones if that's your thing.
White aggro
Slam dunk card at my power level. You can disrupt blockers or more often, blink your stuff while growing itself. Being able to flash it in at EOT to then blink a
prototype card or an
noncreature card is really strong.
I don't quite have enough +1/+1 counters stuff going on in my cube, but if I did, this guy would be insane. For your human theme, this will lead to some crazy turns.

These two together form a very strong combination, allowing you develop your board both wide and tall. Ocelot is a beast by itself and with any equipment/counter/aura it's even more ridiculous. Guide is a life buffer in racing situations and also provides buff + evasion for very little work.
Decided to cut them because
1. Energy
2. Snowballs too hard for one drops, putting too much pressure on the format and making it tough to go for the synergy decks I want to promote.
Sacrifice stuff
These two cards have made Black sacrifice strategies much less narrow and more interesting.
Fantastic glue card for artifacts, sacrifice, blink, counters and humans.
Might be my favorite card from MH3. Having a
Phyrexian Altar on a body greatly diminishes how narrow it can be. It's a lot more than that though as you get an artifact for every sacrifice allowing a host of synergies. And it's a zombie for
Gravecrawler for an obvious combo.
Might be a pet card of mine. I love how open ended it is as sacrificing something as unassuming as a fetch will generate mana or board presence. Crazy with stuff like
Balance or
Wildfire or alongside another sacrifice outlet for double triggers. The base body is a 3/3 menace for 3 which is perfectly reasonable.
Another pet card. "Draw" 3 for 3 is a great rate, but this can also be a ramp spell or a token producer. I need more instants/sorceries for
Young Pyromancer and friends and I have liked this one quite a bit.
Complexity
I haven't tested any of the other flip walkers in this set (even though
Ajani, Nacatl Pariah is an absolute beast), but this is great. It's a one mana creature that produces artifacts and flips into a reasonable walker for slower decks. I might cut it because it's a double face card, but I think it's one of the fun ones.
Great in theory, rough in practice. A 2 drop with GY hate and reanimation potential seems great. So is the fact that if you have counter synergies you can trigger it multiple times. However, with no reminder text for Adapt and Finality counters it gets confusing really fast.
Goyfs
I'm on the fence with this one. It's clearly good enough, it's just a question of what I want to support. Also annoyed that it only checks your GY whereas most other Goyfs check both, leading to some potential confusion.
The Goyfs in this set are insane. This one does everything Black wants with lifelink, selfmill and recursion. In fact it's a little too insane for my tastes as a 3/4 for 3 that fuels itself and gets something back while providing an 6 point life swing is too much. And that is with just creature/land/artifact or something. It can be considerably worse!
Another one I am avoiding for being too dominant for too little work even at higher power level. If it didn't have the last line of text about other Goyfs triggering it, I would enjoy it a lot more. With that line, a clone becomes bullshit IMO, another Goyf is BS too. I lump it with
Gut, True-Soul Zealot and
Broadside Bombardiers as Red threats that will just take over the game if answered.
GY stuff
Ok baseline, with the enchantment type helping with delirium. Granting haste and evasion for a single mana is very good, especially when you can play this from the GY. I have the
LoTR one mana cyclers to help with the Bestow 6 among others which helps.
Probably the best threat in my cube. Grows big (++ with draw 7s), generates card advantage and can have evasion while stocking the GY. Could see this being cut for being too strong.
A plant for more controlling Boros decks. Helps stabilize and close games. While tough to get any GY action in White, Red is really good at it and some
colorless cards help.
Took me a while to find a slot, but getting back any permanent and ramping in the process does a lot of work. Especially when the ramp is in creature form. One of the best self-mill options at that mana in Green.
This one I do not run, but can't really say why. Blocks all day, provides a lot of mana and can be cast from the GY.
Lands stuff
Love this guy because who knows what you are going to do with it. I made a few adjustments for
Six (like
Seal of Fire for a build your own
Molten Vortex), but cycling away dead lands for gas is very strong while also filling the GY.
What a 2 drop for landfall. Makes tokens on the cheap, but also has the option of protecting it behind another creature and potentially getting some stupid boards.
Big two drop that tutors some of your best cards.
Bloodghast makes it trivial to use the ability, but you can usually find fodder to sacrifice.
Ended up cutting this guy because I like other options more, but in a double fetchland format, it is plenty strong.
Utility lands
Really cool utility land. Looks like an expensive creature land, but then you copy a
Bolas's Citadel you discarded and go off.
Included it, but haven't tested. Looks good on paper though as granting haste without going down on mana means you are hitting hard and surprising the opponent. Very good in Modern alongside Phlage for what it's worth and fun to be able to give two creatures haste with the one activation.
Haven't tested either, but this ties discard, counters and sacrifice. Tough to find room at 360(ish).
Whew! Forgot how many I had in the cube and somehow missed a few even then.