Alexander is a root of many names. In Scotland Sandy (for boys) is popular. There seem to be female Sashas around but I always think of it as a boy's name.

Alexander/Alexandra – Short forms, variants and pet names
ALEXANDER (m) From the Greek name Alexandros, which meant "defending men" from Greek alexein "to defend, help" and aner "man" (genitive andros). Alexander the Great, King of Macedon, is the most famous bearer of this name. In the 4th century BC he built a huge empire out of Greece, Egypt, Persia, and parts of India. This was also the name of emperors of Russia, kings of Scotland and Yugoslavia, and eight popes.
ALASDAIR, ALASTAR, ALEC, ALECHJO, ALASDAIR, ALASTAR, ALEC, ALEJANDRA, ALEJANDRO, ALEKSANDER, ALEKSANDR, ALEKSANDRA, ALEKSANDRINA ALEKSANTERI,ALEKSI, ALESSANDRA, ALESSANDRO, ALEX, ALEXA, ALEXANDR, ALEXANDRA, ALEXANDRE, ALEXANDREA, ALEXANDRIA, ALEXANDROS, ALEXANDRU, ALISTAIR, ALISTER, ALIX, ALYX, ISKENDER, LEX, LEXA, LEXI, LEXIE, LEXINE, LEXY, MALANDRA, OLEK, OLEKSANDER, SACHA, SANDIE, SÁNDOR, SANDRA, SANDRINE, SANDRO, SANDY, SASCHA, SASHA, SENDER, XANDER, XANDRA, ZANDER, ZANDRA,
Alexius is another name but some short forms overlap :
ALEXIUS (m) "helper" or "defender" from the Greek name Alexios which derived from alexein "to defend, help". A czar of Russia has borne this name. ALEJO, ALEKSEI, ALESSIA, ALESSIO, ALESSA, ALEXA, ALEXEI, ALEXIA, ALEXINA, ALEXIS, ALEXUS, LEXA, LEXIA, LEXUS
Researched from:
http://www.behindthename.com