Wordpress -3.8 wysiwyg change options available to your user mce options. (colors, HEX, tags) Add more buttons to tiny mce (hr,sup,) (This no longer works in Wordpress 3.9+) Controls: http://www.tinymce.com/wiki.php/Controls

functions.php

// change buttons in WYSWIG post editor, edit color palette
function change_mce_options( $init ) {
$init['theme_advanced_blockformats'] = 'p,address,h2,h3,h4,h5,h6,'; // add tag you want to be available (h1,pre,code)
$init['theme_advanced_disable'] = ''; // includes numlist,blockquote,justifyright,justifycenter,pasteword,pastetext etc.
$init['theme_advanced_text_colors'] = 'FF00FF,FFFF00,000000'; //add your themes colors here
$init['theme_advanced_more_colors'] = false;
return $init;
}

add_filter('tiny_mce_before_init', 'change_mce_options');

function enable_more_buttons($buttons) {
  $buttons[] = 'hr';
 
  /* 
  Repeat with any other buttons you want to add, e.g.
	  $buttons[] = 'fontselect';
	  $buttons[] = 'sup';
  */
 
  return $buttons;
}
add_filter("mce_buttons", "enable_more_buttons"); // add to first row
//add_filter("mce_buttons_2", "enable_more_buttons"); // add to second row
//add_filter("mce_buttons_3", "enable_more_buttons"); // add to third row

This no longer work in Wordpress 3.9+

Color changing can be utilized with the following in WP 3.9+
http://stackoverflow.com/questions/23171247/add-custom-text-color-wordpress-3-9-tinymce-4-visual-editor:

function my_mce4_options( $init ) {
$default_colours = '
"66CCFF", "Light Blue", "005581", "Thor Blue", "01152E", "Dark Blue", "FF0000", "Red", "C0C0C0", "Silver", "000000", "Black",
';

$init['textcolor_map'] = '['.$default_colours.']';
return $init;
}
add_filter('tiny_mce_before_init', 'my_mce4_options');