I haven’t played since MoP and before I buy Midnight I figured I’d catch up properly on my characters by leveling professions in each expansion I missed. In particular I’m interested in things from old expansions that would be worth crafting for use at max. level. To give examples of what I mean - my main has Engineering, and I have things like:
Jeeves
Nitro Boosts
Goblin Glider
Wormhole Generator (Northrend, Pandaria)
MOLL-E
Loot-A-Rang
Blingtron 4000
Thermal Anvil
Locksmith’s Powderkeg (seems to be capped at skill level 35 - is there some upgrade?)
I’ve also found the Wormhole Centrifuge and Blingtron 5000 from Draenor as well as Rechargeable Reaves Battery (with the corresponding modules) from Legion. Is there anything else from those expansions that I missed or that I’m likely to miss from the expansions I’ve yet to reach?
And I’m not just asking about Engineering, it is just a good example since it’s on my main, and it historically has a lot of such items.
As you will have found, the devs have been obsessively limiting the scope of profession items to their own expansion, or levels.
There are a few toy, pet, and mount recipes spread across several professions, but there will be only a very few recipes from previous expansions usable for a 90 in any prof except Eng.
My suggestions
Just look at your Professions for each expansion, and look at the Unlearned tab, and see which of them you want to pick.
Get the addon AllTheThings. It lives up to its name, and lists EVERYTHING, but there are a gajillion swithes and ways to filter, so you should be able to get a view limiting your list to professions.