If you have some spare wall space how about putting up some switched sockets and storing the wall warts plugged in, but switched off, so they are ready to go when needed. Roll up the spare length of the output wires and retain with the usual twist up tie thingy so they don't get tangled but still reach the thing to be charged. Big lable on each wart to identify its use. I'm a great believer in switched trailing socket blocks, all the 13A outlets in my workshop are industrial quality metal clad 4 socket units converted to 6 by replacing the indicator neon and master switch plates with metal face dual socket units. Mine are ex work freebies binned due to lacking ISO 9000 documentation but basic 4 or 6 switched boards can be got at not too silly prices eg around £11 from QVS!
Offcuts of electrical maxi trunking make adequate tray storage for this sort of thing. Probably 50 x 50 and 75 x 75 are most useful. As ever, if you are storing anything with trailing wires or just cables put them into individual plastic bags to keep the knitting gremlins out.
Clive