RPGs and related matters, by Craig Oxbrow.
But what would it include? Hard to do plain Scottish themed without it being tacky. If it were me, depending on the genre of the game, I'd go back to why he is the patron saint, and have his bones being the central theme, with their rediscovery/theft/use being part of a modern day occult adventure. If it were a historic game, or time travel game, then there,s plenty to go on in his Wikipedia page. I especially like the superstition that the St Andrew's cross was co-opted from an earlier hex sign to stop witches flying down your chimney! ;)
I'm not above being tacky, as well you know. :) The relics and reasoning behind symbols would be a good choice - it'd differentiate it from a Hogmanay or Burns Night adventure.