Six new League of Legends summoner icons were released today alongside several other Team Builder improvements, and they're very pretty. As another incentive to use the Team Builder feature, these icons are unlocked simply by playing your favorite role over five matches. And yes, you do need to queue through Team Builder for them to count toward your icon of choice.
The icons cover all six roles: Assassin, Mage, Marksman, Fighter, Tank and Support. To unlock one, just queue and finish five matches via Team Builder as your desired role. For instance, summoners interested in the support icon will need to stick with the role for five matches before the corresponding icon is available. At that point, the icon will pop up as a reward in your client.
Here's what Riot said:
With new reasons to start using Team Builder, we’ve designed a series of new summoner icon rewards for playing the queue. Because Team Builder’s champion select accounts for role, the new rewards are earned by playing your way. After you play five games as one role, tracked in-client, you’ll unlock the icon of that role instantly. And yes, if you’re more of a generalist (or a completionist), you can unlock all six icons.
Be sure to see the full list of Team Builder changes here, on the official League of Legends website. Good luck out there, summoners.