My main interest is writing graphic novels, aimed at (mostly) MG. I also have one idea for a PB that's been simmering for years, and I don't have any others planned.
I see that the recommendation is that one should have 3 PB manuscripts before shopping them. That of course makes sense, any agent or publisher will want to know that a creator is no one trick pony.
Of course, that leaves me as a one-trick pony. It's possible that I could make more PBs but I don't have other ideas at the moment, and my one idea is basically an extended fart joke. So I'm uncertain how or whether I should pursue the idea at all.