My tool kits are custom to each bike that gets ridden regularly, and while there is minor difference they all have similar things:
||Inflating tubes - a minipump is adequate, but on my bent I carry a mini-floor pump which is about twice the speed of a minipump.
||I only carry these during a race or group ride. At $5 a shot locally they're pricy.
|Presta valve adapter
||Cheap thread-on adapter to use car pumps on presta valves - even on bikes without presta valves. They're cheap and small
|Three plastic tyre levers
||Removing tyre from rim, installing tyre to rim. These can break and doing it with one can be a challenge. Orange ideally to not get lost in the grass/dark
|Spare tubes x2
||Because they can wear holes while in the toolbag if not used for a while. Patched ones are ideal.
||Sometimes you have a bad ride and run through all your spare tubes, or might run across someone else stranded/walking because they're under-prepared but you don't have the same tube sizes.
|Multitool or hex/torx tools to suit your bike
||Changing bolts from closed to open and back again
||Luxury tool, but I've needed them several times.
|Chain joiners/master links
||These things break over time, having a couple spare pairs on hand is light and nothing else does the job
|Cable ties and duct tape
||My one clipless bike has some rubber overcleat covers strapped on to aid walking. If I broke down unfixably I'd walk, but that could be slippery and dangerous. Cleat covers go over cleats to add some rubber sole. I'd use the cable ties or duct tape to retain the covers too.
||If the bike has clipless pedals then losing a cleat bolt can cause the shoe to become stuck to the pedal. Can also be used for other things on the bike
||I've bonked before, its unpleasent. A single gel can be the difference. Rotate them out periodically
||Good for drinking, washing out wounds or eyes. Plain water is best for this, additives may sting. For long rides I'll keep one bottle for plain water and perhaps have a touch of lime juice in the other.
|First Aid Kit and space blanket
||Again I've never needed these, but if I did they'd be critical. The Kit is a small plastic box with some bandages etc, and the space blanket is one of those cheap mylar sheets that can be used for warmth or anything
|USB battery and 3 short USB cables
||My gopro needs a new battery to span the commute, so this is my short term fix. The cables are enough to charge my work phone, personal phone, gopro, or a light
||If this bike has a replaceable battery light I will carry a 18650 or CR123A as required
||I hate running out of light on the dark commute, so each bike has normal-use lights and there's at least one spare rear light I don't use unless the others are going out. I have a pocket torch/flashlight as well and have sometimes carried this wedged between cheek and helmet strap
|Rubber glove and pill bottle
||This is for holding all the small parts, and the glove fills the spare space so they don't rattle. I've never needed the glove, yet but silence is its own reward
||The original multifunction tool - not bike specific but a knife is always handy as are pliers
Right now, my road bike has a suspicious cut in the rear tyre. It is too new to just replace so I've added a new tyre to my bag in case it does, but for now I'll keep getting wear out of it. Not a usual item to carry, but in this case its justified. Example of tailoring the gear to suit the needs.
There's also the normal loadout of EDC stuff like wallet/cash and keys and cellphones.
If your bike is broken in a way that allows it to roll still, you can scooter the bike by putting your right foot on the left pedal, lean the top tube against your right thigh, and push off the ground with your left foot (or mirror this if you prefer) It can help to turn your saddle ~80 degrees to the left so you can lean into the corner formed. Expect to do 10-14 km/h on the flat so its faster than walking.
Never ignore the value of knowing when to quit too. A one-hour ride at 30 km/h can turn into a 6 hour walk at 5 km/h. Ringing home for a ride is the last resort, but if you've run out then this can be best.
Carrying a bus/train card might help if the routes are in your favour. Sometimes taxis or uber etc can provide bike-transport services, just ask when you call.
Depending on your country, the local Automobile Association may or may not provide assistance. If you're already a member then check their website or ask.
It is possible and reasonable to flag down other riders if you're really stranded. A coworker once "towed" a stranded cyclist home using a spare tube as a towrope because the bike had some mechanical issue but could still roll.