Additional symbols on the keyboard in the reply form
http://s5.uploads.ru/cFwrl.jpg

Author: Alex_63
Platform: MyBB

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

Code:
    <!-- Additional symbols on the keyboard in the reply form -->
    <style>#keyboard-area{z-index:99}#Add_Btns{margin-top:7px}</style>
    <script type="text/javascript">
    if ($('#post').length)(function (){
      var key,i,j='';key=$('#keyboard-span');

      var arrSmb = new Array (
        '¤','¥','¦','ª','º','&','⊥','¬','‰','µ','¶','¹','¿','↔',
        '⇒','⇐','⇔','⇑','⇓','↵','◊','○','■','▪','▫','≤','≥','≈',
        '≡','²','³','∀','∃','∅','≅','₪','γ','Δ','λ','ä','ö','ü'  //No comma after the last element!
      );

      var app='<div id="Add_Btns">';
      for(i in arrSmb){app+='<input onclick=\"keyboard(\''+arrSmb[i]+'\')" type="button" value="'+arrSmb[i]+'"/>';}
      app+='</div>';$(app).appendTo(key);$(key).find('#Add_Btns input:nth-child(14n)').after('<br/>');   
    }())
    </script>