List of All OTB SharePoint WebParts and Apps?

Hi Microsoft SharePoint Experts,

I am dipping my toe into SharePoint Online, and am trying to build out a new site for my department. Can anybody point me to where I can find a full list of out-of-the-box Web Parts and Apps, the definition / use case for each, and maybe an example. This would be a HUGE help to give me ideas about which to include on my sites.

Thank you in advance!!!