1. Zombie Apocalypse can vary so much (how weak/strong/smart/dumb/etc are the zombies?), but assuming they have power in numbers, and are individually weak, I'll take the L-Star LMG from Titanfall 2/Apex Legends + a bunch of ammo. Should be sufficient to slaughter a horde of them. 2. Oppressor MK II from GTA V. Might not last long, but boy oh boy the chaos :) 3. Command Block from Minecraft OR WorldEdit Mod from Minecraft, either would be sufficient