Counters are pretty nifty little things in Magic: The Gathering. There are counters that have special effects, like those from Liege of the Tangle that turn lands into huge 8/8 creatures. There are simple +1/+1 counters that can give a useful boost to any creature. With Phyrexia invading Mirrodin once again, -1/-1 counters and poison counters are sure to be in abundance. As a Phyrexian ability Proliferate is a really cool ability that can add counters to any permanent or player, which also allows for a lot of neat tricks, going quite well with Infect as well as other artifacts in the set and beyond.
When Proliferate is activated that player chooses any number of permanents/players, adding one counter for one type of counter already on it. If a permanent has multiples types of counters on it, like some charge counters as well as +1/+1 counters, you don’t add a counter of both those types. Only one counter can be placed on each permanent when you use Proliferate. This is an important rule to keep in mind if you start getting all sorts of crazy counters on your cards.
It’s also important to know how +1/+1 counters and -1/-1 counters work. A permanent will never have both of those counters on them at the same time. If both of these counters are on a permanent at the same time, you remove one of each until one type of counter is gone. Since these types of counters cancel each other out, don’t be targeting the wrong kind of creatures or you might end up helping your opponent get some huge creatures!
So with some of the finer aspects of the rules out of the way, what are the coolest ways to use Proliferate? Even looking at just Scars of Mirrodin there are tons of ways to use this ability. Infect, the other Phyrexian ability, is probably the most obvious way to use Proliferate. This ability adds a bunch of poison counters and -1/-1 counters, why not use Proliferate to multiply those effects while still keeping your creatures safe from harm? Proliferate can finish off your opponents’ creatures hit by Infect by piling on some more -1/-1 counters until they reach 0 toughness and are thrown into the graveyard.
Aside from manipulating the counters of creatures, there are a whole bunch of cards in this set and others that use charge counters. Maybe you want to give some of your Infect creatures a big power boost? Normally black doesn’t allow something like this but with a Trigon of Rage handy you can add +3 power to these guys at any time! Normally you would want some red mana so you could recharge the Trigon, but it is here that you really see the power of Proliferate. With something like a Contagion Clasp you can pay 4 mana to Proliferate every turn, adding poison counters to your opponent, -1/-1 counters on their creatures, and charge counters to the Trigon all at the same time!
Looking beyond the set there are all sorts of cool counters that are real nice when you can add them up at an accelerated rate. Planeswalkers are nice targets for Proliferate, being able to give them more loyalty counters, allowing them to perform their ultimate abilities much faster. There are also quest counters from Zendikar. The rare ascension enchantments like Archmage Ascension have really cool effects but they can take a long time before you can make use of them. Proliferate can help you, for example, draw any card you want in only a few turns.
My last tip comes from the Rise of the Eldrazi set with its level up creatures. Those guys can cost a whole lot of mana if you want them to reach the top levels, especially if you have a deck made up of mostly those creatures. Now with Proliferate you potentially only have to pay to level up each creature once. You can then use Proliferate to add level counters to these creatures, even using it to level up multiple creatures at the same time!
These are just a few of the many uses of Proliferate. Any counter at all can be multiplied through the power of Proliferate. Counters that change power and toughness are pretty common in a lot of sets and those can be manipulated with this ability. Charge counters and loyalty counters are usually a great opportunity to use Proliferate and those appear in multiple artifacts and all planeswalkers respectively. Even if you just play Scars of Mirrodin an Infect deck is a great place to add some Proliferate cards to quickly have your opponents succumb to a poisonous defeat!