According to an email received from 1drv@supportcenteronline.com:
Here is the initial list of core domains for OneDrive. Supported IP ports & protocols = :80/HTTP & :443/HTTPS (Note: OneDrive runs as (SSL) secure service, all :80/HTTP requests will redirect to :443/HTTPS) akamaihd.net spoprod-a.akamaihd.net 1drv.com *.files.1drv.com Live.com (recommend opening to *.live.com) onedrive.live.com *.onedrive.live.com *.*.onedrive.live.com storage.live.com *.storage.live.com *.*.storage.live.com *.groups.office.live.com *.groups.photos.live.com *.groups.skydrive.live.com favorites.live.com login.live.com oauth.live.com photos.live.com skydrive.live.com live.net api.live.net apis.live.net docs.live.net *.docs.live.net policies.live.net *.policies.live.net settings.live.net *.settings.live.net skyapi.live.net snapi.live.net livefilestore.com *.livefilestore.com *.*.livefilestore.com MSN.com storage.msn.com *.storage.msn.com *.*.storage.msn.com mesh.com *.mesh.com onedrive.com onedrive.com *.onedrive.com sfx.ms p.sfx.ms
Using this information, I was able to narrow down the list of "never block" items to approximately 8 items. Hope that helps someone else!