Undo tree

(defhydra hydra-undo-tree (:hint nil) " _p_: undo _n_: redo _s_: save _l_: load " ("p" undo-tree-undo) ("n" undo-tree-redo) ("s" undo-tree-save-history) ("l" undo-tree-load-history) ("u" undo-tree-visualize "visualize" :color blue) ("q" nil "quit" :color blue))

(global-set-key (kbd "C-x u") 'hydra-undo-tree/undo-tree-undo)

Every symmetric function pair should have their own hydra - undo/redo included.