I'm dredging this post up while I work on some other things, and because it's worthwhile.
It's reprinted from last October.
FM 21-11 First Aid For Soldiers 1989
The Ship's Medicine Chest USCG 2003
FM 8-50 Bandaging and Splinting 1957
FM 8-230 Medical Specialist 1984
USMC Field Medical Service Student Manual 2008 (multiple lesson links)
Operational Medicine 2001 (multiple sub-lessons and links)
FM 21-20 Physical Fitness Training 1998
FM 8-10-6 Medical Evacuation In A Theatre of Operations 2000
FM 21-76-1 Survival Evasion and Recovery 1999
FM 3-5 NBC Decontamination 2002
FM 21-10 Field Hygiene and Sanitation 1970 (more comprehensive version)
FM 21-10 Field Hygiene and Sanitation 2000
FM 21-10-1 Unit Field Sanitation Team 2002
FM 8-10-4 Medical Platoon Leader's Handbook 2001
TC 21-3 Soldiers Handbook For Individual Operations and Survival In Cold Weather Areas 1986
ATP 4-25.13 Casualty Evacuation 2013
USN Nutrition and Exercise Manual 1999
FM 8-284 Treatment of Biological Warfare Agent Casualties 2000
FM 4-02.17 Preventive Medicine Services 2000
FM 21-18 Foot Marches 1962
FM 8-10-1 The Medical Company 2002
SOF Combat Casualty Care-TCCC 2007
Where There Is No Doctor...Dentist (multiple chapter downloads)
Online TCCC course (individual Powerpoint lessons)
NAEMT TCCC course modules
Johnson & Johnson Ethicon Wound Closure Manual 2005
Emergency War Surgery 2000
USMC Mountain Warfare Wilderness Medical Course 2002 (Windows doc)
Medecins Sans Frontieres/Doctors Without Borders Reference Guides - multiple resources h/t WRSA
Obviously, this is not an exhaustive list. Missing, e.g., is any functional pdf link to the
Special Operations Forces Medical Handbook 2d ed., 2008 which I highly recommend.
(and I deliberately left off any link to the hugely obsolete text
ST 31-91B Special Forces Medical Handbook 1982 which I do not recommend, other than purely as historical reference.)
And there are all sorts of other references out there (some of which I'll cover in the future at some point), but those above are a great place to get started.
Do I want you to become a combat lifesaver, special forces medic, or regimental surgeon with those resources? No. (Of course, if you aim to, the above is your homework; get cracking.) But this list will give you a great perspective on what can (and should) be done, from people who've already done it, under all sorts of adverse circumstances and in multiple environments, and by digging in you'll at least get some perspective on how much you didn't know you didn't know. And not to belabor the point, but most of the other resource texts that you should have are copyrighted material, which you should buy in order to support those authors; the link to get them is called Amazon. Meanwhile, the stuff ginned up by and for the .mil is public domain, by law, and you already paid for it when it was deducted from your paychecks as federal withholding.
The above resources would be sufficient to do a great job in many cases, if you had nothing else available, and would keep you busy for 1-3 years just getting the info into your head.
The links are all current, as of today, but one thing I found in checking sites was that links on the 'Net are an ephemeral thing. Download all of these today, or ASAP, and print them in hard copy at your leisure, after you've flipped through them on your computer.
All of them, together, would fit on a thumb drive. And should go on one, or several.
Pass such a drive/drives along to your group's medic(s), and/or any paramedics, nurses, doctors, etc. you count among your friends. It'll cost you a couple of bucks and some time, but you may equip someone to save your life someday after things get sporty, and possibly even make a better friend.