Emacs: Switch Buffer
- Alt+x
switch-to-buffer
【Ctrl+x b】 - Switch to a file/buffer.

If using emacs 28 (year 2022-06-07), be sure to turn on
fido-vertical-mode
[see Emacs: icomplete mode, fido mode]
If using emacs 27, be sure to turn on Emacs: ido mode in emacs 27