Merchandise
A few items were sold with Co-Optitude branding and catch phrases on them.
Let's Play This F#cker shirt
The "Let's Play This F#cker" shirt was first announced July 23, 2014 on Twitter and was sold through WeLoveFine.
Mug
The Co-Optitude coffee mug features Felicia and Ryon in their 8-bit likenesses from the show intro with the Co-Optitude title between them. The Geek & Sundry online store launched around July 13, 2015, as announced in their tweet. No official social media post mentions the mug specifically, but based on when other people mention discovering the product, it's assumed the mug was a launch product with the new storefront.
Patches
Three sets of sew-on patches were created for San Diego Comic Con 2016 and were later made available on the online store. One set contained Felicia's 8-bit Co-Optitude character and a "P1" (for player 1) patch, and another included Ryon's 8-bit counterpart and a "P2" patch. Each patch is approximately 3 inches in diameter and can be applied using an iron to melt the glue on the back. There was also a third set of Critical Role themed patches introduced at the same time.