I'm of the opinion that there isn't much my credit card can't fix if it's needed. I'd rather not get to that point but it's my last resort.
Safety is most important, make sure your rig is in good working order. Take water and food. Fuel. Communication equipment.
Next good recovery gear. I use this more than tools. Shackles, winch, straps, tire plug kit, working jack, some sort of air up system etc
Then you better have a decent tool kit. I'm not into carrying a bunch of electric tools. I can dismantle my jeep easily enough with ratchets if I have too.
Fluids, spare parts, electrical components.
I keep more stuff in my tow vehicle but I have to have what I need to get back to it.