Deciding who your witnesses are for your marriage certificate can be quite a big decision for some couples (and for others - they're happy with 2 randoms off the street... but I digress!).
Most people just automatically choose their chief bridesmaid & best man... however - it's not mandatory, and it may be a delightful opportunity to include some important people from your life, who unfortunately don't always have a large role in your big day.
Have you considered your Grandparents!!! How lovely would it be to have someone so dear to your heart, who has been there from day 1, to give their official seal of approval on your wedding, by being witness to your marriage.
Bonus points - most grandparents have incredibly neat penmanship & signatures that look beautiful on your certificate!