[book] Proto(?)cyberpunk Book Recommendation – Frontera by Lewis Shiner (bookwyrm.social)
I think this one is a pretty safe recommendation. I found it on a list of protocyberpunk stories a few years ago, and it looks like it shows up on similar lists fairly often, but I think it better qualifies just as early cyberpunk. It was published a month after Neuromancer, and Shiner thanks Gibson and Sterling for their help...