I compiled the list myself. Let me know if anything is missing or if I have some mistakes in there.
Remember that this list only considers self-use of importance, which means that basically anything someone else can make for you to use without you requiring to have that profession isn't a perk at all because anyone can just buy and use that same item. If you can get something with gold, there is no need to level a profession yourself. Resource refinement cooldowns are an exception because they do not require any effort to use, provide a steady basic income and because the supply is so strongly limited that you can't just throw (reasonable) amounts of money at the wall and magically get all of the resources you might require.
Alchemy
- Potions etc: Other alchemists can make them for you, so if you know people and/or have money this isn't really a perk.
- Transmutation: Transmutation is on a cooldown, so the supply of Arcanite on a server is limited by the number of alchemists. This basically guarantees a steady income.
Low self-use but can probably make some money and brings in a good basic income.
Blacksmithing
- Armor/weapons: Other blacksmiths can make them for you, so if you know people and/or have money this isn't really a perk. Random drops are usually cheaper and offer a greater variety of stats.
- Skeleton keys: Can use skeleton keys to open lockboxes and some doors/chests. Can be mostly covered by knowing a rogue but can be useful if your dungeon group doesn't have a rogue with them. Maximum level of keys is extremely expensive though.
- Quest reward (very expensive quest, armorsmith only, additional quest reward seems pretty bad): Glimmering Mithril Insignia
Low to medium self-use if you like the trinket. Might make some money if you get lucky on recipe drops.
Enchanting
- Enchantments, oils, wands: Other Enchanters can enchant items for you and trade you oils, so if you know people and/or have money this really isn't a perk.
- Disenchanting: For souldbound items being able to disenchant is a perk. For anything unbound other enchanters can do the job just fine (or sell stuff, buy mats).
- BoP Trinket: Smoking Heart of the Mountain
Medium self-use if you like the trinket. Might make some money, especially with some lucky recipes.
Engineering
- Bullets/guns/scopes: Other Engineers can craft these for you, so if you know people and/or have money this really isn't a perk.
- Self-consumables (only usable by engineers):
- Bombs/grenades: Deal some AoE damage and stun targets.
- Miscellaneous stuff like target dummies (seems limited in usefulness)
- Seaforium charges: Can use seaforium charges to open lockboxes and some doors/chests. Can be mostly covered by knowing a rogue but can be useful if your dungeon group doesn't have a rogue with them.
- Mortar trinkets (ranged damage, limited charges).
- Repair bots: Having someone who can deploy repair bots can be important in a raid, although very expensive.
- Self-use items/equipment:
- Specialisations: A lot of the craftable stuff can be used by the other specialisation, exemptions are:
High self-use, especially for PvP. Won't make any money.
Leatherworking
- Leather/mail armor, ammo bags: Other leatherworkers can make them for you, so if you know people and/or have money this isn't really a perk.
- Doesn't seem to have any BoP recipes beyond crafting Ogre Suits for DM tribute runs from BoP ingredients (can also be created by a tailor).
- Deeprock salt cooldown: Refining Deeprock salt is on a cooldown, so the supply of deeprock salt for Cured Rugged Hides is limited by the number of leatherworkers on a server. You might be able to sell these.
No self-use. Might make some money. The steady income is nice but probably lower than from tailoring and alchemy.
Tailoring
- Cloth items, bags: Other tailors can make most of these for you, so if you know people and/or have money this is a limited a perk.
- BoP items: You can craft yourself a very good robe (+ ogre suits, see leatherworking), the recipes can be found in dungeons or bought on the auction house. Truefaith, Archmage, Void
- Mooncloth cooldown: Making mooncloth is on a cooldown, so the supply of Mooncloth on a server is limited by the number of alchemists. Mooncloth is required by everyone who wants the best bags or epic cloth items. This basically guarantees a steady income.
Good self-use if you want one of the epic robes. Selling bags can make you a little money, as does good basic income from mooncloth cooldowns.