Extra Batteries for ear-pro and red dots and all the sight tools if something is loose.
Second the sight tools. Any AR-15 or AK-47 sight tools are a must. Even if the sights are zeroed, you never want to be unable to make adjustments.
I recommend setting out each firearm, especially those with lasers, back straps, optics/red dots, weapons lights, and other accessories such as angled foregrips and slings. Locate all the necessary tools to install, remove and adjust every fastener on every gun. I'd also include a cleaning rod that screws together in sections, a small brass mallet, and a Glock Tool or set of small punches.
If you shoot ARs, include a spare parts kit in case you lose/break/wear out a spring or pin.
Put all the tools in one container. For organization, maybe get a small, clear plastic organizer box with dividers. That way, whether you're at home or the range, you'll have every possible contingency covered, and the tools can be located quickly.
If you have room, you can include the extra batteries mentioned in the box, so you aren't caught with a dead red dot or laser.
Get some screwdrivers that work with your fasteners, such as flathead drivers with the squared end, to avoid stripping certain screws.
If you shoot steel plates, maybe extra hardware that can get damaged, or or for target frames that might. I also carry a Leatherman with pliers.
Cleaning supplies would be good, such as rags, patches, brushes, or a bore snake. A small can of Ballstol can come in handy, too.
Whatever lube you use on the guns, bring a little just in case a gun appears to need a little more. If you clean and oil your guns before each range visit, this shouldn't be needed, but what happens when you take a gun out to shoot that hasn't been used/cleaned in months?
If you shoot corrosive ammo (Mosin), bring a couple ounces of ammonia Windex or other base liquid to neutralize the acid from the ammo, so it's not eating your barrel before you get time to really clean it.
You'll know what's needed when you set out the guns to do the inventory. If you need a 1911 bushing tool to break it down or a jeweler's screwdriver to adjust a sight, you can make that call as you go.