Microsoft GUID (********-****-****-****-************)

5x5 (*****-*****-*****-*****-*****)

Use random chars

Use letters

UPPER CASE (A-Z)

low case (a-z)

Use numbers (0-9)

Use additional chars ( )

User's chars (put without any delimiters) 

Use prefix 

Use mask with  as wild char

Limited by length

 Minimal password length

 Maximum password length