Knowledge Base
How to Show All Sites You Have Access To in Sharepoint Online
Step 1: Log in to Office 365 and go to Sharepoint Online
Step 2: In the search box type in contentclass:STS_Site
Step 3: A list of sites that you have access to will be shown
Other Commands
If you need to see all site collection + subsites , search for “contentclass:STS_Site OR contentclass:STS_Web”