There are a number of VG-based flavorings. The majority are PG-based. A number are also a combination of the two (such as 24/73 PG/VG, with the difference being flavoring, alcohol, water). Nicotine can be used PG- or VG-based.
Off the shelf, the majority of flavorings seem to be PG-based. Depending on what company you are ordering flavorings from, you may be able to specify what you would prefer. This might be much more common with flavor companies that will do custom wholesale orders than with off-the-shelf retail companies, I'm sure.