Strange that you're downvoted. Everyone I know is in the same position.
Office 365 for Office apps because they are standard and available offline.
GSuite for better email, calendar and web-based real-time collaboration.
Slack because it has the most integrations at this point.
Box (or Dropbox) for file syncing because their apps are nicer and faster, although Dropbox controls are subpar compared to Box. Both will exist for a long time since OneDrive is utter crap and GSuite Drive File Stream is extremely slow and unreliable.
Office 365 for Office apps because they are standard and available offline.
GSuite for better email, calendar and web-based real-time collaboration.
Slack because it has the most integrations at this point.
Box (or Dropbox) for file syncing because their apps are nicer and faster, although Dropbox controls are subpar compared to Box. Both will exist for a long time since OneDrive is utter crap and GSuite Drive File Stream is extremely slow and unreliable.