The survivor/prepper movement is rife with good ideas for homemade (of necessity) tools of various sorts. In the extreme situations posed by their premise, there's always a need for fire starting tools, first aid kits, water purification techniques, etc. If you haven't previously encountered their perspective, it's worth considering and at least a bit of investigation. Start here with these videos:

The Ultimate Pocket Survival Kit by SuperEnginerd


Micro Emergency Fire Starting Kit Tutorial by MeZillch


Biosand water filter DIY homemade survival water filter by desertsun02


Ultimate homemade survival kit by ArmyRanger10a


Homemade Survival Kit by thesurvivorguy3