Hard (or even not at all) to find the sockets for ZM1000 nixie tube, but easy and cheap to make these yourselves. I did not check this for other types. I think the pictures show it all.

Supplies

Flat, or single cable as found on the internet e.g. for arduino projects

Step 1: Nixie ZM1000 Socket

Sockets for nixie tube ZM1000 are hard (or even not at all) to get. As can be seen on the pictures you can connect to the pins easily with a cheap flat (or single) cable. These cables are sold for cheap on the internet (e.g. as used for Arduino)

Step 2: When the Wire Connectors Are to Thick

When wire connectors including insulation are too thick as for example the nixie NH-2 you could use
single Du Point connector pins as can be seen on picture.