Not sure how to phrase this, but I’m aware that “real” pop-ups/unders open an actual new window or tab. Much more common these days are the annoying giant ads that pop up IN THE SAME TAB as you are reading a webpage, thus blocking the view. Sometimes hitting Esc gets rid of them, sometimes not. What’s the proper name for these, and is there any add-on that blocks these? I assume the answer is no, but I thought I’d ask.
Mozilla calls them “In-Page Popups” and had created a reporting extension for these: https://addons.mozilla.org/en-US/firefox/addon/in-page-pop-up-reporter/. Not sure how that project is going.
Some also call them overlays or dialogs.
I think uBlock and similar can block some of these “annoyances” but by far not all of them.