Driving a 20+ year old vehicle, I tend to travel heavy. In the rear I carry my 3 1/2 ton floor jack (handle stored crosswise in front of the rear bench seat on the floor), complete 3/8" socket set under the rear bench, 1/2" breaker bar and socket set in the rear A/C cove, brake flare kit in the space under the passenger side rear bench seat, complete 1/2" short socket set under the middle bench seats, crimping wrench and complete fitting kit under the driver side of the rear bench. 1/4" drive set under middle of mid bench seat. Toolbox with common sizes of flat and Phillips screwdrivers and cold chisels, pliers, Torx/Allen bits and cordless drill behind rear benches. All common sizes offset and combination American wrenches from 1/4" to 1" in 12 point and Metrics from 7mm to 20mm also in 12 point in toolbox behind rear bench. These are ALWAYS in the vehicle. When going long distance I carry clamps of varying sizes, extra vacuum lines, copper brake line lengths, and organizers with all the various bolts, screws, nuts, and whatnot that might be needed in a pinch. I've always driven older vehicles / muscle cars that require 'extra' love on the road. What odd / extreme items have others found useful when emergencies arise?

 

AAA and Amex cards

 

I don't do it as much these days but for a long time, my excursion has been a diesel-powered toolbox. I used to travel to the aircraft that needs wrenching so I typically have all the tools plus the assorted aviation-specific things like sheet metal tools etc.
A few of my favorites,
The Puma PD1006 is hands down the best portable air compressor I've had. Coming up on 10 years and it's still chuggin'. I mostly use it for a tire inflator, but it has bucked quite a few rivets and run air impact in short bursts. That little compressor earned its place as a "don't leave the driveway without it" tool.
For any electrical woes, I really like Milwaukees M12 soldering iron. It has replaced very expensive butane soldering irons and their hazardous exhaust port. Nice bonus it is compatible with Hakko 900m tips available in bulk for a lot less than the branded Milwaukee ones.
The aluminum 3-ton jack from Harbor Freight has also earned its service badge as a permanent fixture. Like most things from that source, buy it with a bottle of jack oil. The weight savings over the steel equivalent are very noticeable.
For diagnostic, I scored a panasonic toughbook on ebay for less than $100. The only thing it does is run forscan and php hydra tuner, along with assorted manuals and other pertinent references. The battery doesn't hold a charge and the screen is a bit dim but it stays in the ex with an adapter to plug into the 12v port. If it gets dropped, or soaked ( and it has) it's no big deal. Lately, I have been entertaining the idea of diy'ing a replacement.

 

I carry a USAA insurance card, a tow strap, ratchet straps, a few folding chairs, an umbrella, 1 wife, 5 kids, 2 dogs, a glock with extra mag and a olight flashlight.

If I travel with it then a tool bag, a hammer, jack, cordless impact. And a for sale sign. Never know what I would sell first, the wife or kids to fix the truck.

 

In no particular order: ratchets and sockets, selection of wrenches,leatherman tool, selection of rubber hosing, silicone emergency tape, selection of heat shrink butt connectors, wire, extra coil pack, M18 impact and lantern , bottle jack, 4x6 cribbing blocks , soft shacklez, tow strap , via air pump and $500 in cash. Amazing what you can get done with a stack of $20’s if you break down after hours or need to be moved to the front of the line at the shop.

Got most of in a 30qt Yeti load out box cash i have hidden.

 

USAA isn't what it used to be. I had a continuous policy with them for about 26 years or so, filed one claim on my RV at about the 23-year mark, they denied it.

Moved to the greater San Antonio area (the home city of USAA), and they were literally double the price of every other major insurance carrier. After fighting with their automated phone line a few times, I finally just said the heck with them and cancelled everything I had with USAA, even moving my investments out of their banking side.

Sadly, USAA is just as expensive (or more expensive) and just as crappy now as everyone else. If you haven’t shopped around in a while, I suggest you do, what you find will surprise you.
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That's sad to hear. I've had USAA for a long time, just never had to use it. I do hate having to call them now that they have gone to the automated menus.