How do you get the FPX Thresh Signature Icon?
It was a mission or event reward. Riot's description in the client reads: “Honoring Crisp's winning Thresh in the 2019 World Championship.”
Is the FPX Thresh Signature Icon still available?
No. Riot tied the FPX Thresh Signature Icon to 2020 (mission reward), and it does not normally bring back past event rewards or bundles.
