How do I open separate tabs/windows for all buffers in Vim?

To split all buffers use :sba or :vert sba

Vim command :sba has also a shortcut: :ba.

:[N]ba[ll] [N] :[N]sba[ll] [N] Rearrange the screen to open one window for each buffer in the buffer list.

To back again to single tag, use: :on (:only).

:on[ly][!] Make the current window the only one on the screen. All other windows are closed.

To quit, use: :qa

See also: How to convert all windows into horizontal, vertical or tab splits? at Vim SE