Here are some of my favorite things for oboe/bassoon/general music:

Husky mini screwdriver from Home Depot (includes three flathead tips that fit the oboe, and the tips are stored inside the handle). It's also easier to grip than the ones that normally come with oboes.

Oboe Adjustment Guide by Bruce McCall - Has clear pictures on every page and isn't confusing. :)

Nylon upholstery thread from Hobby Lobby (cheaper than double reed shops and lasts forever)

Collins scented cork grease

Parafilm tape - translucent stretchy tape that only sticks to itself. Good for sealing reed leaks in a pinch, and looks better than teflon tape.

Adjustable music stand shelf - holds your reeds and tools during rehearsal

I have a black fan that blends in during concerts and helps me keep myself and friends cool under hot stage lights.

Vandoren Reed Resurfacer and Stick - This is an etched glass rectangle and stick used to adjust/sand reeds. It is reusable and washes with soap and water.

Tupperware "Midget" cups - these are great water-tight cups for reed soaking. I have gotten several on ebay.

Standaconda - silicone sprial to keep loose music stands from sinking (nice for when you have a heavy binder/tablet on your stand). These are a little pricey but work well. Other solutions include large binder clips and hair clips!

Magnetic reed soaking cup

CRKT Ruger Folding Pocket Knife. This knife is awesome for reed adjustment and has a black blade (blends in on stage).

Cleartune app - I use this tuner on my phone

OCB non-gummed cigarette papers - gets water out of the pads and tone-holes.

Aquarium tubing to keep English Horn reeds on the bocal (double reed shop tubing is the same stuff, only more expensive). I have also used this to create spacers between bassoon bridge keys (doesn't damage the instrument.)

Black padded cosmetic bag - When directors tell double reed players to leave our cases off stage, we still have tons of stuff we need with us. This helps hide our swabs, tools, extra reeds, etc. on stage.

Grunwerg Mini Thermos (200 ml). The smallest black thermos I could find - I bring hot water for my reeds and it stays warm for hours.

O2Cool necklace fans - good for outdoor performances and marching band practice (the black blends in)

Tonal Energy Metronome App - the best metronome I've found for visual learners (myself included)!