>>168486By what criteria? And how specific? I'll throw out some areas for example.
TOOLS, LOTS OF TOOLS. This can be anything from screwdrivers and wrenches, to band saws, welders, maybe a forge even, and other fabricating tools (along with the expertise to utilize, or the wherewithall to learn). I'm not proficient with 3d printers, but absolutely if they can be had. This isn't limited to fabrication tools either, garden and agriculture is essential if one wants to reduce or eliminate a dependence on grocery stores and basic infrastructure. Viable seeds and enough land to produce on are also essential, and will largely determine how many people such a community can accommodate feasibly.
>Solar panelsThis
>>168544 anon is correct, solar is only viable if one (or the group) has the resources and means to replace them. Good luck making your own panels from scratch is all I'm saying, but you can make a wind turbine from scratch with a few magnets and some thin boards or repurposed equipment (ceiling fans, my dude).
A plumber, or an individual with some such experience should not be overlooked, as an off-the-grid community can't just call a plumber if there's a problem.
Communication will also be an issue. Yes, we all 'love' our cellphones, but a HAM radio operator is also a good addition, in general day to day as well as in the event of emergency (ESPECIALLY a breakdown of communication lines).
To that covers food, water, electricity, communication.
Guns and ammo of course, but with kid gloves; the atf would
love to go apeshit on some "crazed wackos on a compound" (rather, they
have).
To really fill out an 'essentials' list, that depends on how "off the grid" the group is able/willing to operate. I've met 10 year olds who have never even seen a TV, let alone a TV program, and their favorite thing to do (
as a hobby, for entertainment) is to chop wood.
Where there is a will, there is a way, but that should give a pretty good outline.