I always have recovery gear, folding e-tool (military shovel), axe, leatherman rebar, lightweight tarp, kindling and ferro rod, water filter, 100' of paracord, disposable gloves, hand sanitizer (cleans pitch and grease and doubles as fire starting excellerant), well stocked first aid kit, fleece sleeping bag liner, hammock, folding 3 legged stool, zip ties, fenix HM50R headlamp with spare battery. Probably forgetting something, but all of that fits in my Besttop saddle bag with the axe handle sticking out a bit on one end.
In the Winter time I have another bag I throw in with extra layers, blankets, energy bars, snow boots.
If heading out on a long trail, I throw in a bag with basic mechanics tools, 5 gallons of water and sometimes my snowshoes.