I've been riding mountain and road bikes for many years but feel the need to get out and explore the dirt. On the road I've always been a bit of a minimalist when it comes to my toolkit, a multi-tool with chain breaker, a spare tube with CO2s, and a quick link. On the mountain bike, my pack includes all those plus a few spare bolts, a quick link, and a pump in addition to the CO2. For gravel I lean toward that minimalist side. For typical day rides, is there anything I should add to my kit?
Hopefully you are running tubeless, in which case you should add a couple tire boots (dollar bills work in a pinch) and a tire plug kit. If you regularly travel in nasty terrain which could clog up a drivetrain (or obstacles which could rip the RD off your bike), you might want to carry a spare derailleur hanger. (Caveat: I only carry that last item if it's a long and nasty race.)
I travel light. A tube, Pedro levers, a co2 (with a piece of tube around it), valve, multi-tool, and a Fiberfix emergency spoke. Same for road or gravel biking.
Thanks for the tips. I'm not running tubeless yet since I'm using tires left from my CX racing days before tubeless was really an option. I've used it for years on my mountain bikes and know how great it works. For a tire boot, I've always used gel wrappers. On anything but the shortest of rides I always have one in my pocket. I always carry a spare derailleur hanger on mountain bike rides and it has saved my butt more than once. Unfortunately both my current gravel bikes are steel and do not have replaceable hangers.