Notable.
The Drupal Devel module offers a Function Reference that is helpful. To display it, enable the Devel module, and then place the Devel block in one of your theme's regions.
You will see a link to Function Reference, which leads to here:
http:/www.yoursite.com/devel/reference
You can, however, customize the function list in a way that may be more helpful.
Theme functions
print '
';
$functions = get_defined_functions();
foreach($functions['user'] as $function) {
if(substr($function, 0,6)=='views_' || strstr($function, 'views'))