If I'm riding somewhere out of town solo, I'll carry a small first aid kit along with my diabetic supplies. Since I utilize the large Topeak seatbag, space isn't a problem. I always carry a pump, Topeak Road Morph, that will inflate a road tire.
Out on the trail, I always have a first aid kit, and I may start carrying a snakebite kit. My son crashed lat year and aroused a hiding rattlesnake! The snake was more scared of us and slithered away with haste.
Never forget a phone, identification, and heath insurance card. I can be admitted with my insurance card.