How do you get the Honor Great Teammate Icon?
It is an Honor reward. Riot's description in the client reads: “Earned by obtaining a Great Teammate ribbon, or by being in the top 10% of Teamwork honors in your region before the Honor 1.0 system retired.”
Is the Honor Great Teammate Icon still available?
Riot does not list the Honor Great Teammate Icon as a legacy icon.
Honor Great Teammate Icon is one of the rarest LoL summoner icons.
