First Aid Kit - Zombies are dangerous but so are infections from minor cuts and lacerations. Gotta prep for the unexpected.
Machete - Most effective and common sense weapon as all the others require some level of skill or maintenance and only the machete would be good at making pointy sticks for improvised spears.
NVGs - Something people forget about is that when the power goes out you’re going to be looting some dark ass buildings even during the daytime. Stock up some batteries or a charger and looting just got so much simpler. Plus, if you hear a bump in the night, you can go looking for it without letting the neighborhood know where you are, like with a flashlight.
Water purifier - You can go approximately 3 days without water and the pipes stop working when the electricity does. That river and lake isn’t safe to drink, neither is the rainwater, and do you really want to whip out your firekit and draw attention just for sippy sips?
Boring picks but I think these are the biggest bang for your buck. Everything else will take so much just to maintain that it isn’t worth it. Including doggo.