Welcome to Wattpad Help Wanted, the one stop shop for all your Wattpad related wants and needs!... except it's free so it's technically not a shop.
Moving on!
I've noticed that there are a lot of different groups on Wattpad, and since they don't actually have names for some of them, I made them some. You got your
Authors (who write books :O shocking, I know)
Chatter boxes (I'm sorry, I couldn't think of anything else. they use Wattpad as a social media site like facebook, twitter, tumblr, buzzfeed, and blog by using their boards, pm, and works)
Reviewers (people who review author's books)
Critics (don't get mistake them for reviewers! There will be fire, pain, and lot's of blood. I think the difference is that they are more private than reviewers and don't announce their critique, and instead work with the author over pm)
Grammer Nazis (teh guyz paniking ova teh fakt thta im spelin' bad)
Artists (they make art! cover art, character art, art projects, crafts, etc.)
Bards (they write poems, songs, prophecies, etc)
Consultants (these guys help with info. They know the names of all the characters in the fandom you want to write about. They know fighting styles, weapons, super powers, and weaknesses. They know planet, city, and ship layouts. They know whatever you need to know. But good luck finding them unless you get a fact wrong)
Editors (unlike critics, these guys completely help with any tiny mistake and some will fix the mistake themselves. they offer help with how to make the story better in every aspect)
Agents (They help get your story out there by publicizing your story. they also help you find all the other Wattpad groups you might need help from)
Co-ops (a mix in between author and editor. They help write a story with someone)
Readers (they just kind of... you know. Read.)
Generators and Creators (they generate stuff, titles, plots, settings, etc.)
Trailer Makers (they make promotional trailers for your books)
and many others!