Boards (Super Mario Galaxy)
From the Super Mario Wiki
“Your world's a great place! If you need a sign, I'm your guy!”
 Gil Board
Gil Board is the first of the boards to be encountered. He is a signpost that tells Mario how to Wall Jump. He claims to be the "Famous Gil Board" and claims Mario knows him, although Super Mario Galaxy is the first appearance in which he has been specifically named. He appears in Honeyhive Galaxy.
 Bill Board
Bill Board is the second board encountered, and the Board with the most appearances. He teaches Mario how to roll the Star Ball in the Rolling Green Galaxy, Melty Molten Galaxy and Rolling Gizmo Galaxy. He also makes an appearance at the celebration in the Grand Finale Galaxy. Here, he tells Mario that he lives in a nice world, and that he would be able to enjoy it more if he wasn't a sign.
In Super Mario Galaxy 2, he appears in the Rolling Masterpiece Galaxy, once again teaching Mario how to roll on the Star Ball.
 Phil Board
 Jill Board
Jill Board is the fourth and final board to be encountered. She reminds Mario how to control his Boo Mario form. Her only appearances are in Boo's Boneyard Galaxy and Ghostly Galaxy, where she only speaks to Mario when he is in Boo form. If Mario talks to her in Ghostly Galaxy while not in Boo Mario form, the text that instead says "(This is written in Booish)", which might mean that the Boards have writing on them, even though they can speak.
 Names in Other Languages