Mouse: quickly roll wheel down twice (when scrolled to the bottom)
Keyboard: End / Space (when scrolled to the bottom) or Ctrl + End / Ctrl + Space
Mouse: quickly roll wheel up twice (when scrolled to the top)
Keyboard: Home / Shift + Space (when scrolled to the top) or Home / Shift + Space
Personal script. Refrain from feature requests.
Tested with Scriptish (Firefox) and Tampermonkey (Chrome).
For best results, websites should take advantage of the two link relationship attributes rel="next" and rel="prev". If these attributes are missing, the script has to guess the best link based on label ("Next", ">>", etc.).