Use magit? Have a lotta buffers? This is handy.

gistfile1.txt

;; Unrelated to the above, but handy anyway                                                                                                                                                                                                 
(defun ibuffer-mark-most-readonly-buffers ()
  (interactive)
  (ibuffer-mark-on-buffer
   #'(lambda (buf)
       (and
        ;; Yeah, yeah, I could (defvar                                                                                                                                                                                                      
        ;; ibuffer-precious-read-only-yadda-yadda) but screw that.                                                                                                                                                                          
        (not (string-match (rx bos "*magit: ") (buffer-name buf)))
        (buffer-local-value 'buffer-read-only buf)))))

(define-key
  ibuffer-mode-map
  [remap ibuffer-mark-read-only-buffers] 'ibuffer-mark-most-readonly-buffers)