Here, sometimes I use:

 ALT 35    for   #

 ALT 128    for   Ç

 ALT 135    for   ç

 ALT 129    for   ü

 ALT 64      for      @

 ALT 164    for   ñ

 ALT 168    for   ¿

 ALT 173    for     ¡

 ALT 225    for   ß

 ALT 58    for   :

   The ones that I use more; there was a time in wich my mouse didn´t work properly at my workplace and these above helped me a lot.    It slowed me a little bit, but it was better than not typing at all.