Do you mean the connectors or the adapters (3 pins to 4 pins molex)? I think I have some connectors on hand (new, you need to conect the wires to the pins)
I ended up using the connectors from usb and audio headers(they had single connector ends *1 pin plugs into 1 connector). If you have any of those laying around. Cut the single connector ends with some wire still left, strip part of it and twist it together with the wire from you fan. Add a little electrical tape and you got it. A local PC shop might have that in an old parts bin?