I accidentally removed an account from my w10m and most of my contact disappeared from People app.
How can I recover them? I have a number of backups on my OneDrive.
In order to use the backups, you'd need to do a hard reset (which wipes everything on your phone), then log in to the same MS account and restore from the backup. If you have multiple MS accounts and one of them is working on your phone, you can copy the contacts over. To do so, follow these steps:
In the top menu bar, click on Manage → Export contacts. Follow the steps to save the contacts to a file.
Repeat step 1, but log in with the other account that's configured on your Lumia.
In the top menu bar, click on Manage → Import contacts. Follow the steps to import the file you saved earlier.
Allow some time for the phone to sync the account, and the contacts should show up on your phone again.