Alchemist's Supplies: Basically the standard alchemist, creates potions and bombs. Potions could produce temporary or lasting effects on living creatures (super-soldier serum). Classic targets of the alchemists were the philosopher's stone (turn lead into gold), panacea (cures all ills), and universal solvent (dissolves anything--probably the closest real-world analogue is hydrofluoric acid). This could theoretically serve as a replacement healer if you don't have a cleric or druid. The biggest question about the universal solvent--how do you store it? Can be flavored as a protoscientist, medieval apothecary, or witch.
Brewer's Supplies: similar to the alchemist in that they produce magical liquids, but in much larger quantities. A magical brewer might be able to brew potable water or liquid nutrition (recall beer was a source of calories in some cases) or even potions from the dank water found in dungeons, not to mention being a nice source of income and entertainment for parties outside of dungeons.
Calligrapher's Supplies: makes scrolls, of course, but can also produce hypnotic patterns (or ones that cause charm spells if your ethics allow) or other mind-affecting effects with their supernatural handwriting. In a darker, Lovecraftian-themed campaign, their calligraphy may open the way to Things From Beyond--or close it. Calligraphic patterns may leap off the page as creatures or spell effects.
Carpenter's Tools: making wood golems and devices is the obvious thing, but could also build shelter (Leomund's Tiny Hut, Mordenkainen's Magnificent Mansion) or supernaturally enhanced barriers and fortifications. Monsters are coming--an enchanted 2x4 can become a door with a command word. For Christian gamers, this could also have spiritual aspects--remember Who the most famous carpenter in the world was.
Cartographer's Tools: The map isn't the territory--or is it? A sufficiently powerful magic cartographer has a reality-warping ability to make passageways, doors, or even small islands appear or disappear. Archmage cartographers can rewrite reality--as it is drawn, so it shall be.
Cobbler's Tools: magic shoes, of course. But those don't have to be limited to boots of speed; they can be weapons (boots of kicking), travel (boots of striding and leaping), cast mind-affecting spells (oxfords or high heels of allure) or travel between dimensions. Could even power a bard variant that uses dancing rather than magic to cast spells.
Cook's Utensils: there's at least one anime about cooking and eating the monsters you find in the dungeon, at least some of which might give you some of their powers properly prepared (quite a bit of folklore about this). Magical meals could have healing effects or produce buffs such as haste, bull's strength, etc. And, of course, it could be poisoned with curses. Any magic that produces effects on a living creature could be produced.
Glassblower's Tools: glass is fragile, but could be easily shaped into enchanted grenades. Also note that glass is, ironically, chemically resistant, so the glassblower could produce coatings that protect against acid. Purely artistic effects could have charming, hypnotic, or even dominating ability--look into the creepy Black Glass of the Dark Lord and you will always do what he says. And, of course, enchanted glass could bring movies to your fantasy world before anyone invents celluloid or cocaine.
Jeweler's Tools: enchanted jewelry is a staple of already-existing D&D--look at all the crowns, rings, bracelets, necklaces, and the like. In addition to the usual magic items, shiny stones could entrance or hypnotize, shoot rays of fire (lasers!), and cursed ones could be radioactive (and the decay products themselves might be something else, something dangerous.)
Leatherworker's Tools: well, you can make clothing and leather armor, so enchanted boots, belts, and leather armor are obvious. Making your stuff out of monsters might grant some of their powers (cockatrice gloves create a petrifying touch a la Nethack), and the fact that you have to actually kill something (or, for really dark games, someone) to get your best stuff could be explored as a moral dilemma. Books bound in leather might have enchanted abilities. Other applications for leather depend on your game group.
Mason's Tools: a bit slow for dungeoneering, but you can make powerful golems, shelters and fortresses, and possibly even weapons for the technology-averse. Masons are strong--this character could double as a fighter-type in a pinch.
Painter's Supplies: as suggested above, paintings can come to life, as items, spell effects, or monsters. The pigments might have magical properties--perhaps certain reds inflame the viewer, or blues put them to sleep. And, of course, gettiing the best ones might require a quest.
Potter's Tools: we all assume the magic of a potion comes from the contents, but what about the container? A magical potter might make vesels that turn their contents magical a certain number of times a day. Magical pottery might even be more resistant, and a pot of holding isn't that much nuttier than a bag of holding. Magical pots might entrap enemies like a genie in a lamp, possibly forcing the monster to grant a wish when released (it attacks you on a 1). Oh, and clay golems.
Smith's Tools: the fighter's best friend. This artisan makes all your magic weapons and armor, quests for the right metals and fuel to make them, and is burly enough to help the fighter if necessary. They can also make fences, doorknobs...and iron golems. (Cue Ozzy...) If your characters want to be Iron Man in the Middle Ages, this is where you start.
Weaver's Tools: enchanted clothes are a staple of folklore, from cloaks of invisibility to thinking caps. Almost any effect can be applied to an appropriate piece of clothing--you can also have embroidery that comes to life or enthralls or hypnotizes.
Woodcarver's Tools: similar to the carpenter, but their creations are likely to lean toward the artistic. As such, in addition to mind-affecting spells, they might actually encode spells like a scroll, or be able to trap monsters in a woodcarving that later come to life.
And for fireball...some of them might be flammable.
