Of all the archetypes in the cube UG +1/+1 counters is probably the one most dependant on one of it’s colours (green) and it’s multicolour section. Blue provides some good cards but not a huge amount of them. Luckily the odds are good that you will get these as they are rather low picks for other decks.
I actually incorrectly believed that this deck had won the cubes first real outing (possibly due to it absolutely steamrolling me repeatedly with Gyre Sage > Fathom Mage > Lorescale Coatl > Prime Speaker Zegana. I have since been informed that it came in in second place getting beaten in the finals by a deck I have sadly forgotten.
If you get the right cards this one, as you can imagine from the above, can turn into an almost unstoppable engine of grindy card advantage. Granted it can fall completely on it’s arse as well, perhaps more than anything but the tribal decks but that’s the gamble.
I would also say that it’s also probably the least “all-in” deck in the cube usually playing a tempo strategy with some late game inevitability.
There are plenty of sources of counters throughout the cube, the most common being evolve from RTR block. Most of the good evolve creatures are in, especially the ones with any kind of interesting effect (most notably Simic Manipulator‘s mind control ability, Gyre Sage‘s ramp and Fathom Mage‘s card draw). There isn’t really a huge deal to be said about the evolve ability.
There are also creatures with incidental counter abilities such as Undergrowth Champion, Lorescale Coatl and Prime Speaker Zegana. If all things go well in this deck you should accumulate plenty of counters during the normal course of events without actually having to put too much effort in. The ultimate version of this is Master Biomancer.
This leads of course into why you should bother going out of your way to pick up plenty of +1/+1 counter generators during the draft…
The payoff cards for +1/+1 counters are a little limited in the current build and something I’m looking to improve but you do get a few good ones.
Renegade Krasis is another entry on my ever expanding list of cards which I wished had worked in standard….or anything for that matter. In theory he should be pretty good here so long as you have plenty of creatures with counters and can keep up the flow of guys (combos nicely with Fathom Mage).
There’s also Vorel of the Hull clade who can take any creature with a reasonable number of counters on it and turn it into a potentially game ending threat. Like Renegade Krasis he also combos with Fathom Mage to get you burning through your deck.
A Sample Deck
Illustrating my point above this deck came out as a fairly normal UG midrange deck with plenty of draw and a counters theme (sticking Vorel does seem pretty good here, especially with a counterspell up).
In the next big round of changes this archetype will get a bit of refinement, hopefully with some new releases as it needs some more cards to make it clear that this is actually a thing to draft.
PS: This is Daghatar, FEAR HIM, FEAR HIM.