There are five guns/rifles everybody should own.
You name three: shotgun, suppression rifle (AR-15) and handgun.
Add sniper rifle (deer hunting quality rifle) and .22 rifle (quieter, small game, universal ammo).
If SHTF ammo will be the new currency. Specifically .22 cal ammo. BLOAT.
That’s expanding on it a bit. The classic trifecta is still the bare minimum, IMHO.