Shoes (with cleats in good working condition)
Helmet
License
Bike (in good working order: washed, lubed, adjusted, good tires, good brake pads, good chain)
Directions to race and map
Shorts/Skinsuit
Fingerless gloves
Jersey (SS/LS)
Undershirt
Socks
Cold-weather items:

Vest
Jacket
Arm warmers
Gloves
Leg warmers/knee warmers
Ear band
Booties
Hat
Leg embrocation

Wet-weather clothes:

Rain cape/vest
Cycling hat

Sunglasses (dark and clear lenses)
Sunscreen
Chamois cream
Safety pins
Water bottles
Race food, drink, and salt/electrolyte tabs
Post-race nutrition
Face towel
Leg towel
Post-race towel
Post-race clothes and shoes
Garbage bag for wet clothes
Extra wheels
Tools for quick fixes (extra bar-end plugs, allen wrenches, chain lube…)
Tools and tubes to fix a flat
Floor pump
Rollers or trainer for warmup
Toilet paper
Medical kit
ID
Foam roller
The Stick
Special nutritional needs, such as Peet’s coffee