Topo has been doing these "X" collaborations for a little bit now; you'll find Topo X Howler Bros., Topo X Salomon, Topo X Woolrich, etc...products all over their website. I think it's a pretty interesting branding exercise, and from their generous use, one that I suppose works well for them, especially when the two companies offer complimentary products.
Personally, I'd love to see a Tenkara Company TBD X Vedavoo or X ZimmerBuilt collab (although in the case of the former it happened in a limited way, and in the case of the latter I guess there is sort of one right now, without as bold of a dual-branding marketing message).
There's probably also an opportunity for a performance fishing apparel brand too if both parties found it to be mutually beneficial.
Nike X Simms...eh, that'd never happen...
Or maybe brands just don't mean that much to you. I'll be honest, most really don't mean a ton to me, but a few do resonate since I've had nothing but positive experiences with their products. It'd be cool to see them working together, especially if the end product was unique and brought some added value.
One could take this in all sorts of humorous directions, but I was curious if there were any collaborations in the fishing world that you'd like to see actually happen?