Every since my time at vocational school for aviation maintenance and
maintaining my own light aircraft, I've bought crimp tools from B&C
Specialty Products:

https://bandc.com/product-category/electrical-supplies/tools/

For automotive stuff, probably the RCT-1 is the one you need.  I've had
several.  (I keep losing them!)

The Ideal Sripmaster 45-097 on that page also is one of my favorite tools.

I also keep a stock of FastOn terminals and butt splices from B&C:

https://bandc.com/product-category/electrical-supplies/terminals-and-splices/

With the right crimp tool, those terminals and splices create a better
gas-tight crimp than the stuff available at West Marine or auto parts
stores.

I also keep several sizes of Mil-Spec Tefzel wire on hand:

https://bandc.com/product-category/electrical-supplies/wire/

It's punishingly expensive, but I prefer for the same reason it's used
in general aviation: The Tefzel insulation is far more resistant to chafing.

I especially like the shielded, multi-conductor Tefzel for stereo wiring.

I always believed the extra cost is worth it.  A scary example was when
the decades-old, dealer-installed, un-fused air conditioning wiring in
my 1984 Westy finally wore through, causing a fire near the fuel filler
with my nephew strapped in the back.  Nothing like that ever happened in
my planes.

Here are a couple of my projects using B&C supplies:

https://sbw.org/westybattery/

https://sbw.org/westydisplay/