DBML doesn’t seem to recognise UUID as a type. It would be nice.
Hi Paul, I’m Jia Wen from the dbdiagram.io team! Thanks for your post!
dbdiagram.io do support all data types, as long as it is a single word after the column name. The data type will still be displayed in the visual diagram plane.
Is this what you wanted to do regarding UUID? Why do you feel that the UUID data type wasn’t recognised/supported? 
My guess is because it does not auto-complete like the rest of the types. I thought the same thing.