* Ads in YouTube feeds for other google products and services.
* Ads underneath videos for products from the channel owner.
* Sponsorships within videos from the channel owner.
* Advertising overlays (supported IN THE APP BY GOOGLE) for products and services from the channel owner.
* Email advertisements for Google products and services.
* Community post advertisements from channel owners which show up in the YouTube feed.
I contacted support to enquire and they state these are not considered advertising.