a firebrick in a tray (jewelers work surface) for small things that are best done with a torch, I recommend the hard firebrick, sold for around $4, with spray on liquid rubber covering 5/6 faces + rubber feet. Ceramic tile is too slippery to be useful, maybe teracotta.
and, catalytic butane heater for teflon heat shrink (blows electricity out of the water), IMO blows a hot air system out of the water for small electronics applications. If I am doing a big box I work in the garage with a proper hot air gun, but still inadequate for teflon heat shrink.
small precision machinists vise for dead bug work on bigger packages (i.e. doing a mounted to chassis to-220 with resistors and capacitors soldered on to it directly, i.e. voltage regulator). Feel like it has to be a good expenisve one though, using clips/panavise/etc for this sucks
small ESD mat cut out for soldering on, that you ground and put on top of your normal mat, so you can use good goopy flux without destroying a big expenisve ESD cover. You can put it on top of some kind of substrate, i.e. wood, with a small bezel, so it can be handled nicely (not floppy), like a micro picture frame
small wire rack for laying finished connectors on (think of the thing above your BBQ for heating bread), what its good for is if you do a coaxial connector that you solder the shield on. They will be hot when you are done, so you can lay the hot part on the wire rack and because of the geometry round things will get slightly wedged in there so they do not roll around and cause problems/injury, I mean to make a creative one with multiple wire spacing so it can handle SMA, BNC, and N-sized things. Needs to be a little heavy so it can resist the force of the cable laying on it (i.e. LMR400 cable). So you don't hang them off the side under a book

cleaning kit : organized kit with precut towels of various sizes and types, Q-tips, wooden sticks, etc. You can chop up some kitchen towels (I recommend a mixture of the premium shop absorbent towels and more abrasive cheap scrubby napkins). If you have a few sizes to choose from you can quickly choose the right size without having to tear corners of towels and make a mess. If its available you tend to use it rather then leaving small 'problems' for later in an attempt to economize on using a single towel. Very helpful if you are using glues, obviously pair with a small bottle of rubbing alcohol (i recommend you get a 250 ml bottle to refill from a big bottle of IPA)
silicone mat : if you like to use the hot glue gun on the work bench
small 'modular' work holder for pliers, I keep mine assorted as in an armory on a top shelf, but I will usually figure out what I need to use for a particular job and it comes down to only a few, so its useful to have a temporary holder for these things
exacto tray, so you can lay a exacto blade in there safely
small goose neck weighted lamp if you are working on something that ends up having annoying shadows (it should be well lit but you might find angles in a chassis that do not light well *battery powered obviously).
typical lab bench : house with marble floor with no furniture in it
another one is a custom 'less safe' soldering iron tray, so you can lay down a soldering iron without aiming it into a hole every time, gets old with repeated work, but not have it lay on the ESD mat like people normally do when they get tired
I made this stuff so I don't know if they sell particular products for it, usually I find custom is more ergonomic
block of wood with a few holes in it for driver bits, a slot for a good machinists ruler (choose your favorite from the wiha storage box (you can't work from a bit box)
small hand held battery powered vacuum cleaner (i.e. AA) for quick clean up of small wire cuttings (say you shave a ferrule), paired with some kind of quality tray for stripping wires over.
Honestly though, I recommend a separate technician bench for as much of this as you can get away from the test equipment with. When it gets complicated/big enough, it starts to feel like having a kitchen inside of a garage.