lots of questions from members who want to do DIY driveability issues with no basic diagnostic tools to do them.
what are some of the must have's with all the common blazer quirks?

I believe a minimum would be:
1: basic code reader
one with a live data stream would be better.
2: a DVOM
a power probe would be even better, (combi voltmeter, circuit tester, test light)
3: fuel pressure tester.

 

sawzall, torch, cut off wheel. hammers, pry bars, bazoka

 

Compression tester,
Cylinder leak down tester, Air Compressor required
Code reader, OBD II will work for newer. if you can find one with ABS And supports OBD I with the adapters for cheap GO FOR IT!
Misc. Pullers 2-3 jaw.
Ball-Joint/Tie-Rod/Pitman Arm/Idler Arm service tools depending on how far you want to get into your rig
Grinder, Dremill, grease gun, obviously grease ha ha, Vise 6" or so. I got a harbor freight 12T press in my shed.. hardly ever use it.
Small torch (Walmart/Meijer) is what I use and it did fine on my u-joints


So I guess buy what you need as you need it.

 

Not necessarily for blazer specific quirks but, Id say the two specialty tools i use the most in the shop are:

Ball joint press
Ft/lb torque wrench

 

Hands, that have joints that you did not know about and are only unlock-able through cheat codes.

 

Google.

As for tools... Scan tool and leak down tester. Vacuum pump.