Where do you find fellow collaborators in a given field of expertise?

I am working on a couple projects related to databases and blockchain-esque data structures, and as such have been searching for some other folks with overlapping interests to work with me on these projects. Of course it's not really appropriate work for someone fairly new to engineering -- I'm looking for people that can work with me on product development in addition to technology, people who can offer genuine insight into my space.

I've been having a lot of trouble finding folks like this. It seems like there'd be some amount of interest in advising a project from the ground floor, but can't determine where the best place to go to "recruit" is. Wondering if anyone has any suggestions for me?

Thanks!