Well, almost all tiles; the few that remain after running the script below (save as unpin.ps1 then right click and "Run with PowerShell") can be removed manually (right click tile > "Unpin from Start").
UPDATE: A smaller and more efficacious PowerShell script by max630:
(New-Object -Com Shell.Application). NameSpace('shell:::{4234d49b-0245-4df3-b780-3893943456e1}'). Items() | %{ $_.Verbs() } | ?{$_.Name -match 'Un.*pin from Start'} | %{$_.DoIt()}
/windows | Feb 04, 2017