Here we have a wire needle type fid.  This is ideal for smaller rope sizes, that the hollow type fids are too big for. 

I have used these for between 6mm up to 8mm rope with no problem.  I am sure they will also work with larger rope too.  As you can see they are good down to at least 3mm, although this size rope is rather fiddly.  I have never been able to pull the core out of rope much smaller than 5mm.  

Ideal for pulling thin kite lines etc. through protective sleeving.  

I have also had some success with paracord.

They have approx. 200mm of 0.7mm stainless steel wire and enough rope to pull them with.   The wire is attached to the rope very securely so will not pull out.