[...]
C-x w 2 split-root-window-below
C-x w 3 split-root-window-right
C-x w s window-toggle-side-windows
C-x w f tear-off-window [ mnemonic "frame" ]
C-x w t window-swap-states [ mnemonic "tranpose" ]
C-x w - fit-window-to-buffer [ like C-x - ]
C-x w { shrink-window [ like C-x { ]
C-x w 0 delete-windows-on [ like C-x 0 ]
Less sure about these being useful enough, or what keys to use for them:
C-x w + balance-windows-area
C-x w . minimize-window
C-x w b replace-buffer-in-windows
By default, windmove binds shift-left/right/up/down for moving in those directions, and winner binds C-c left/right for undo/redo'ing window configuration changes. I imagine that many people here have established habits for these (if they use them), but, for example, both "left" bindings are also used in Org, and the default machinery for windmove includes an easy way to replace the Shift modifier with another. How about:
C-x w left windmove-left
C-x w right windmove-right
C-x w up windmove-up
C-x w down windmove-down
C-w w C-z winner-undo
C-w w C-S-z winner-redo