After you collected your town ruins scavenge tools and signal urbans SHTF set, this is god time to think about additional item s which can make your action easier after city collapse.
First it might be good to have some more personal protective equipment as joints (elbows and knees) protectors. Ruins is not friendly environment and during ruins exploration a lot of injuries may occur. Especially knees and elbows are exposed.
This is good to have googles. When your hammer strikes rubble splashes may hurt eyes.
Ear protection as small and lightweight and can make your life easier.
This is good to have some sand bags to reinforce after SHFT shelter and/or protect from bullets.
Nails, wood saw and small hammer are useful during small wooden structure building. Metal wire and different tapes is good supplement of all set. This is good to have urban camouflage tape.
And in the end. Item which really can save your live is mirror. This is much saver to explore unknown rooms behind corner using mirror instead of exposing yourself to be a target of hidden or surprised attacker.
Now with all this equipment it will be easier to scavenge on civilization remains. What about looking for useful items in abandoned cars?
See what is worth consideration.