What do Jay, Nick, Daisy, Jordan, Tom, and Myrtle lie about?

This depends on what you mean by "lie".Of course Myrtle is lying to George about her affair with Tom and Tom is doing the same with both George and Daisy. Gatsby doesn't outright lie, or at least we are never told about it. He keeps his business very secretive and he might extend the truth (like attending Oxford for longer than he did). I can't think of Nick outright lying though.

I am talking about different types of lies that occur in the story. If you read "The Ways We Lie" by Stephanie Ericsson she explains 10 different lie.