I just stumbled on shift+enter to page-down in vim. I'm wondering if there is something as useful (i.e. easier to reach than ctrl+B) for paging up. I'm looking for something that is already there, not a custom mapping.
Ctrl+d will scroll the window down and Ctrl+u up. It might be easier to reach as you avoid the right ctrl.
This is not the same as page-up/down but you can configure it to be using the 'scroll' option.
From the help (for ctrl+d):
Scroll window Downwards in the buffer. The number of lines comes from the 'scroll' option (default: half a screen).