Button pasting BB-tags of indentation [indent]
Adds the tool for regulation of indents before the word and above the line, does not move to a new line
http://s2.uploads.ru/3yim7.jpg

Author: Deff
Platform: MyBB

To HTML-bottom (Admin → Options: 2nd form):

Code:
    <!--Paragraph tag - [indent] -->
    <style>#button-indent {background:url(http://s7.uploads.ru/t/mnkgq.png)no-repeat center 6px!important;}</style>
    <script type="text/javascript">(function(){ var b = '[indent]';
    $("#button-strike").after('<td id="button-indent" title="Отступы"><img src="/i/blank.gif"  onclick="smile(\''+b+'\')"></td>');
    var indent = '<span style="display:inline-block;margin:1em 2.1em;"></span>'; /*double indent top and left*/
    $('.post-content p:contains("'+b+'")').each(function(){ $(this).html( $(this).html().replace(/\[indent\]/gm,indent));});}());
    </script>

Version where you can set your own values [indent=2,5]
Red - left indentation, blue - top indentation, all in em
Top indentation blue (with comma) may be absent => [indent=2]
or the same version without top indentation: [indent=2,0]
both indentations may be absent => [indent], default indents
Values can be fractional (with dots): [indent=2.3,4.5]

<style>#button-indent {background:url(http://s7.uploads.ru/t/mnkgq.png)no-repeat center 6px!important;}</style>
<!--Paragraph tag - [indent=X,Y] --><script type="text/javascript">
(function(){var c="[indent",h,e='<span style="display:inline-block;margin:YYem XXem;"></span>';
$("#button-strike").after('<td id="button-indent" title="Indents"><img src="/i/blank.gif"  onclick="smile(\''+c+']\')\"></td>');
function a(b,d){if(!d){return e.replace("XX","2").replace("YY","1")} /*double indent top and left by default*/
else{return d.replace(/=(\d+(?:\.\d+)?)((?:,\d+(?:\.\d+)?)?)$/,function(f,i,g){h=e.replace("XX",i);v=g.substr(1);return h.replace("YY",(v?v:"0"));
})}}$('.post-content p:contains("'+c+'")').each(function(){$(this).html($(this).html().replace(/\[indent([=\d\.,]*?)\]/gm,a))})}());
</script>

Paste sign "=" (equal) and your values to the tag [indent=3,4] by yourfelf!
If you need not an empty tag, but a tag with default values (that would be comfortable to change) after clicking the button, then replace the blue line with the following:

$("#button-strike").after('<td id="button-indent" title="Indents"><img src="/i/blank.gif"  onclick="smile(\''+c+'=2,1]\')\"></td>');