When you delete stories or collections they can be recovered up to 90 days since deletion.
Look for the trash can icon near the team name on your dashboard:
Next to the icon you can see how many items (where you are a collaborator) that have been deleted in the last 90 days for any team you are a member of.
Pressing on that icon will open a panel on the right of your screen:
Simply press the 'Restore' button to move any of those deleted items back to your dashboard.
Please note: Stories and collections will not be recoverable beyond 90 days after they were deleted