I see Autolycus has already been mentioned, but in addition to kitchen implements I’d like to add Japanese culture. Right? Or maybe just doing it to hot Asians. I don’t know now.
Guess what my expertise is! Guess, I tell you!
Euthanasiast: Writing pit OPs.
ultrafilter: Along with math and weightlifting, metal.
Omphaloskeptic is another math dude worth mentioning.
jshore on climate.
GaryT on cars (along with Rick and Tuckerfan)
I think the chemists deserve some credit:
The Cocky Watchman - Organic Chemistry
Solfy - Organic Chemistry
Chaotic Bear - Organic Chemistry
Squink, clearly knows more than his fare share of chemistry, but I haven’t quite been able to nail him down.
Also, while I specifically labeled them as organic chemists, they clearly have demonstrated that they have enough chemical knowledge to be some of the best the board has to offer in general chemistry. They aren’t just engineers with two semesters of organic behind them.
snerk If I was, I’d make more money.
Actually, I wonder if Squink is a chemical engineer. He seems to know a lot about industrial chemical processes.
zoogirl, my partner in all things Alice. 
elmwood - urban planning (or something with cities?)
matt_mcl - Montreal Metro system, French
Biffy the Elephant Shrew - progressive music
Cunctator - all things Sydney
Lsura and Frank - how to frequently relocate
Elmwood - Cleveland
DoctorJ - Drugs in Appalachia
TomnDebb - Cleveland and Detroit
Ed Zotti - Alternate identities
Ed Zotti helped me sneak into the East German intelligence agency in 1984 just for shits and giggles. FTR, there were no Big Brother posters or two-way TVs. I was disappointed.
Still, makes for a great story.
I didn’t see anyone else mentioning him…
RTFirefly - Math in most of its complicated forms.
Jonathan Chance, were you gone for a while or something?
Baker has first hand knowledge of Westboro Baptist Church.
Bibliocat is a paramedic, I believe.
**lissener **is a knitter.
St. Urho is an EMT.
Johnny LA: helicopters, flying small planes
OpalCat: stripper life
Eve: golden era of Hollywood, book writing, transgendered culture/experience
And, huh. When I think of equine experts, the people who came to mind were Spavined Gelding and…oh, hell, what’s her name…she brought me over to COTH (the SDMB of the equine world). I think her s/n on COTH is ChestnutMare, but I don’t remember her s/n here. Stupid headache. Anyway, I know** EddyTeddyFreddy** is, too, so that makes four of us Doper equestrians that I know of. My branch of equine expertise, not that anyone asked (or mentioned) would be horse racing.
I bow to the collective brilliance of the Dopers.
Isn’t Shagnasty also a pilot? Should go in with Johnny L.A., who I think has already been mentioned.
Emergency Medicine and transport - StUrho and Cartooniverse both are/were in the field.
Botany - Maastricht is a Dutch botanist, I believe.
Military Affairs - has anyone mentioned Paul in Saudi or Tripler yet? And Airman Doors of course.
That’s gotta be an awesome job! 
Dutch Botany does indeed sound like an intriguing euphemism.
Euphemism? Hell, it can mean exactly what it says and it would still be an awesome job.