Banners
There is a few types of banners. The main ones are fixed, adaptive, sticky and video.
The fixed is what you see most of the time a stationary banner it maybe a gif or a still, the main thing is positioning of the banner and what websites you are it is going to be shown on. Some companies allow you to bid on the websites you want other rotate your ad through the network of sites they have available.
Adaptive is the same has a fixed but it changes sizes if its a app user or website.
Sticky is in a cover of the screen or at the top. It is also know as a floating banner.
The video are interesting, much like a sticky they'll sit in the corner of the screen. You have the choice to play with sound on or off. I am pretty sure they auto play but I have never used them yet.
The main Sites I been using are: