Brave has at least two kinds of ads at present: Sponsored new tab page backgrounds, and user-controlled mechanism that delivers ads as toaster popups. The sponsored backgrounds are on by default, the popups are not. The toaster popups have a revenue share thing where Brave gives a cut of its ad profits to users so they can use Brave's tipping service to benefit creators.

Brave Talk and Brave News are ad-funded as well but I haven't tried them so it's hard to say.