Otaku Pin Club. Yes, they are a club! HAHA.
On the real though, Otaku Pin Club is a brand that creates all your favorite anime series into pin forms. Anything that you can think of, they have created pins for, such as you Rem fans from Re:Zero to Kamina from Gurren Lagann (such as myself).
There’s not that many pin brands out there, and being such a pin junky as myself, I just had to check out their work.