I started looking into the world of Prepping after doing an online course run by The Red Cross (
https://www.futurelearn.com/courses/natural-disaster-safety ) which encouraged me to put together a 'grab bag' of things needed in case of having to leave the house in a hurry (below).
I've gone beyond that and now have a limited supply of tinned food, a small Camping Gaz cooker (and cartridges) and some bottled water in storage.
The problem with looking at this is - 'where do you stop?'. If you look at the various prepping forums they are heavily influenced by American mindsets of bugging out into the wilderness and living on stewed raccoon. Even without this there's a mindset among British preppers that you need survival skills (and the tools that go with it) - which is fine as a hobby-mindset but fails the reality that most of us live in a relatively densely packed country with excellent infrastructure and pretty good back-up services for when things do go pear-shaped. (Of course if you do live out in the wilds YMMV).
The plague times taught us some valuable lessons about what to stock-pile (in moderation) and the dangers of panic buying - we weren't overrun by Bad People breaking our doors down and we didn't need to arm ourselves to the teeth.
The Preppers also get heavily into Communications - whcih assumes that the mobile phone network fails completely. I'm in the lucky / unusual position of having a Ham radio licence (Amateur Radio) and have a range of HF, VHF & UHF radios in the house, including PMR (& potentially CB) - I really, really can't see the scenario where I'd need to resort to any of it.
For reference my Grab Bag currently contains:
Copy of relevant pages from passports; Home Insurance details (renewed every spring when the clocks change); Contact list (renewed every autumn when the clocks change)
Note paper & pencil; Two foil blankets; Two Buffs
One small bottle of hand sanitiser; One small cake of soap & Washcloth
Batteries - 5 xAA 10 x AAA (renewed every time the clocks change); Torch & Battery light
Five small chemiluminescent lights; Set of folding eating utensils; Two different small multitools,
Cash - £10 note, 2 x £5 notes, 30 x £1 coins (Total £50)
20 water purifying tablets; Wind-up Radio (MW, SW, VHF) includes USB charger, light & siren
Headphones (Earphone type); USB cables - both mini & C type
Painkillers - Paracetamol, Tramadol, Co-codamol & Ibuprofen
Simple mobile phone & Multiple new SIM cards; Velcro cable-ties
Spare glasses; Toothbrush + small tube of toothpaste; Tooth repair stuff
Roll of loo paper + pack of moist wipes; Minimal First Aid kit; 1 litre empty drinking bottle