Sometimes, it's easier to make your own and let members come to you. But a lot of our members will either post things in the Character Development section [with lists for things like Enemies, Friends, romances, etc], or when they make a new app, they will just post a thread for that character.
To be honest, a great deal of our plotting happens between members via cbox, PM or other chat method, though we do encourage people to use the RP Request as much as possible.
So, honestly, it's a game of either picking a character you're interested in and contacting that member, finding their plotter or looking in the dev section. Typically we have plot pages in the RP Request section and Shippers in the Dev section. But I don't think most characters actually have shippers anymore.
As tempted as I am to suggest that everyone should be asked to make a list, those threads get very long and eventually need to be moved to a new one, and some members only want plotting for a specific character at one point or another. So we can't really require it to work a certain way.
I'm not saying that, as Admins, we won't consider making a suggestion, but we've never had a rule about that, preferring to let members be creative with how they ask for plots. Jackles has a few threads up that you might want to look at, with examples of different ways to post. I.E., post your characters, or ask for people to tell you what they need filled so you can provide hole-filling characters, etc.