Optics greases and fader greases, likely to be available at least under the counter from relevant speciality shops that offer maintenance, are couple of alternatives you could try in that they offer similar quality of smooth heavy movement without being overtly sticky against small corrections.
But you might just end up paying nearly as much for something you don’t find quite as good, and since Nyogel 767A is actually available from European shops these days (as above) with non-hideous prices I’d just grab a tube.