Formal:
* Brouillon: This is the most common and general term for a rough draft.
* Ébauche: This term is a bit more literary and implies a more preliminary sketch of an idea.
Informal:
* Premier jet: This literally means "first throw" and is used to describe a first attempt at writing something.
* Version de travail: This means "working version" and is a good option when talking about a draft that is still in progress.
You can also use a phrase like "une version préliminaire" (preliminary version) or "un texte de travail" (working text).
The best way to choose the right term depends on the specific context of your conversation.