1. Precompute a list of recipe scrolls linked to the recipe they teach.
2. Scan a character's learnt recipes when they open the tradeskill window. You'll need to open the tradeskill on each character.
3. Use the above data to get the list of unlearnt recipes.

The feature came up out of a desire for a way to scan for recipes unlearned across the account. It would be great if CTR could store known recipes for each profession known and show missing recipes from those professions. I would assume most players would want these results to be realm specific so they aren't seeing recipes for alts on a realm that can't learn it.

1 is the blocking issue - got the datasets, but need to write a script to connect it together, and need to fully automate the process so I'm not left compiling the data indefinitely.

I can put an "For all realms" toggle.

Update: Written a script to get recipes to spell ids data.