Stuff I like to do with UG:
-- Aggro
It's worth distinguishing between aggro (base-green for undercosted beaters, with blue offering interaction that green doesn't have access to) and tempo (base-blue for cheap evasive creatures, with green for pump and good rates on gold cards). Edric is great in tempo but average in aggro; one reason I like tripling up on Noble Hierarchs over stuff like Elvish Mystic is that it's good in both of these decks (as well as everything else). Green also has lots of flash creatures that fit well with blue's instants.
If you really want to push the flash angle, consider:
Wolfir Avenger;
Yeva, Nature's Herald;
Prophet of Kruphix;
Briarhorn;
Rewind;
Plaxmanta;
Shambleshark;
Caller of the Claw;
Silumgar Sorcerer;
Horizon Chimera
-- +1/+1 Counters
You have the cheap evolve guys, ways to grant(/graft) counters, and cute synergies with persist and the like. Fun cards here include Mirrorweave, which is Plague Wind if used on a graft creature and solid Wrath protection with persist/undying/Chasm Skulker; and Rapid Hybridization, an unusually solid trick in blue and a 1-mana 3/3 with upside on a leftover body.
-- Ramp
I've seen a few types of ramp deck:
- Generic ramp: usual ramp effects into planeswalkers, large creatures, and spells like Primal Command. The de facto best deck in the MTGO Cube(s) for a long time
- Turboland: focuses on Explore effects, Courser/Oracle of Mul Daya with library manipulation, and the like to accrue a lot of mana without dipping low on raw card count. I like this one because the cards moving back and forth between zones tickles me for some reason
- Primeval Titan: often a subset of Turboland and works best with the ULD, the idea is to use Titan and other cards to get maximum value from specific lands rather than just amassing a lot of them. Shelldock Isle is excellent here
- hyper-ramp: most ramp decks want to go 2-4-6 (like the old Wolf Run Ramp decks in Standard) or just play a 5-drop a turn early or something. With hyper ramp you use cards like Prime Time or Gilded Lotus (or Thran Dynamo in power-max Cubes but I try to steer clear of that) as your payoff cards to move up another tier: X-spells, Eldrazi, Ugin, whatever
- creature ramp: uses mana creatures to ramp into something that relies on having lots of creatures e.g. in BG you can ramp into a massive Mycoloth or Tar Fiend. Chord of Calling fits into this category, not sure what else does.
- combo ramp: here you're just trying to build up and stay alive until you can cast something that wins the game by itself. Scapeshift is the obvious example in Constructed but it's hard to make it work in Cube; something like Ugin qualifies, as does Upheaval, Avenger of Zendikar, Time Spiral. This deck wants cards like Moment's Peace, Cryptic Command, or Cyclonic Rift a lot more. A subset of this is the 'Heartbeat deck': anything that untaps lands (mainly the Urza's block free cards) with Heartbeat of Spring, Karoos, etc.
-- Creature Shenanigans
This covers all the Green Sun's Zenith/Birthing Pod/Chord of Calling/Survival of the Fittest/whatever decks. Green has the cards that find creatures, blue has some of the better ones to find (since Counterspell/Boomerang and the like are all stapled to creatures nowadays) as well as Brainstorm/Ponder/Tracker's Instincts and ways to loop creatures with Crystal Shard alongside Erratic Portal/Temur Sabertooth.
also:
- Protect the Queen: UG has lots of ways to protect a creature (Sylvan Safekeeper, Spellskite, GEArchmage, Vendilion Clique, countermagic) and good creatures to protect (Master of the Wild Hunt, Consecrated Sphinx, Polukranos, Master of Waves, Primeval Titan, Oracle of Mul Daya, Wolfir Silverheart, Whisperwood Elemental, Meloku)
- Tokens: Green isn't one of the main token colours, and blue certainly isn't, but that's changed recently between Chasm Skulker, Master of Waves, and Reef Worm. Green gives anthems/Overruns and you have Blasting Station/Eldrazi Monument as colourless incentives.
- Morphs: Probably only suitable if you dial down the power, but the morph enablers and most of the good morphs are in UG: Aphetto Alchemist, Broodhatch Nantuko, Den Protector, Icefeather Aven, Rattleclaw Mystic, Stratus Dancer, Temur Charger, Tribal Forcemage, Voidmage Prodigy, Deathmist Raptor, Ainok Survivalist, Shaper Parasite, Shorecrasher Elemental, Thelonite Hermit, Vesuvan Shapeshifter, Brine Elemental, Sagu Mauler, Quicksilver Dragon, Thousand Winds, Chromeshell Crab
- Tap/Untap: With Pestermite/Exarch, Quirion/Scryb Ranger, and Kiora's Follower, there are lots of ways to get multiple activations of a looter/Waterfront Bouncer/Fauna Shaman/Imperious Perfect/Ulvenwald Tracker/Master of the Wild Hunt/Dreamscape Artist/Stampede Driver