You can only "discover" recipes that belong to sets you already have unlocked.
You can only unlock a set by starting with it, or reading the recipe that is found from scavenging.
What items you grind on does not affect what you discover.
There are exceptions. Basic recipes and those that aren't parts of sets- You learn some based on your skill level - for example hats in most armor skills, or plates in basketry.
The other exception is Toolcrafting, Masonry, and Woodworking. None of these pieces are in sets, and are learned what seems to me to be randomly. Its not clear to me if Architecture is in sets or not.
As with everything in Xsyon, this is just a theory, based on my experience in game, discussions in vent, and reading on forums. Nearly nobody knows anything for a fact about the mechanics of this game. That being said, I am yet to see this disproven by anybody who wasn't confused.
To help clarify, lets take Rubicon Loin Guard as an example. Rubicon is the set. In order to learn ANY Rubicon pieces, I must already know at least one Rubicon piece. So I must either have a Rubicon piece as one of my starter recipes, or I must read a recipe for a Rubicon piece. Once I have learned at least one Rubicon piece, the others will quickly be discovered by grinding anything in tailoring.
As for baskets, there are at least two Container Sets. Pauwala and Hugaleti. Each set has a number of different size containers. If you do not know any container peices, you will never discover them.
I hope this helps clear some stuff up for people and saves them some time.
I started as a Architect and went to go look for nails and cloth for a tarp, i started to grind all the extra cloth i had and i went from 5-12 in tailoring, i learned how to make a hat when i only had the basic thread/cloth recipes.