First time posting. Thanks everyone for the great community and information. Recently I've been working on setting up Brewtarget. I was initially frustrated at the lack of default ingredients I could use.
To fix that, I created a GF version of the Brewtarget sqlite db. It removes all fermentables with gluten (and yeasts) and adds in ingredients used in GF brewing. It's by no means complete and not perfectly accurate. There's only one recipe entered. Hopefully it can be useful to others. There is a zip file with the sqlite db as well as exports of the fermentables, yeast, and misc tables. (the ingredient xmls aren't beerxml)
The simplest way to use it is to rename the sqlite file to database.sqlite and drop it in the Brewtarget data folder. Using the Merge and Restore options might work as well. I haven't experimented much.
Edit: Grain.bsmx file for Beersmith 2. Again, not perfect. Basic color and yield only.