The Commanders that have utilized his tap ability the most are Meren of Clan Nel Toth and Prossh, Skyraider of Kher. Prossh seems the more natural fit, as he brings with him a number of 0/1 Kobold tokens equal to his converted mana cost. Getting at least 7 3/2 Horrors for only 2G and a tap is pretty significant. Add to that many Prossh decks play Purphoros, God of the Forge, so that's often going to be 14 damage to each opponent! Keep in mind that Prossh brings more tokens into play each time he's cast from the Command Zone, so the Evangel's ability becomes even better!
Meren decks are more concerned with the war of attrition, and winning that war through reanimating a creature every turn. It's incredibly relevant that you're often going to get 2 or more activations of the Evangel a game in a Meren deck more often than you ever would in Prossh, where it's more often a one-shot effect. In Meren, you're playing Dictate of Erebos and Grave Pact to take advantage of your sacrifices, forcing opponents to sacrifice a great many creatures when you play Evangel and use his ability. Also, when creatures die, Meren gets you more experience counters, meaning you can reanimate bigger stuff on each of your upkeeps. Fun times!
Another really good fit for Emrakul's Evangel is Mazirek, Kraul Death Priest. Giving each one of your creatures a +1/+1 counter when any permanent is sacrificed is very strong. The only issue is that the tokens themselves don't benefit from Mazirek's ability, as the counters are placed on creatures before the tokens ever resolve. While it's not perfect synergy, he still works in the deck, regardless.
Pretty much any token based deck that's good at spitting out 1/1's can use Emrakul's Evangel. Rhys the Redeemed decks, for example, can use anthems such as Glorious Anthem and Dictate of Heliod to make the Horrors even more deadly. Also, Cathar's Crusade, one of the best +1/+1 counter producers in the game, triggers for each creature that enters the battlefield. If you make 10 tokens, you get 10 +1/+1 counters on each creature you control, including the tokens themselves! Seems like a natural fit to me!
There was speculation that the Evangel could play well in a Standard environment along with the potent token producer Secure the Wastes. That never came to fruition. But Secure the Wastes sees play in Commander, so It's rather likely that Secure the Wastes and the Evangel will be played alongside one another for years to come. The Evangel is a great creature for Commander and it's really not seeing nearly the play that it should!