What are some other gases that liquify at around the same temperature as ammonia?
Wikipedia has a large list of gasses in ambient conditions here as well as a list of refrigerants here. You can sort them in order of boiling point by clicking on the small black triangles just underneath the respective column. Then just look for things in the range of ammonia, which boils at -33 °C under 1 bar. Note that a large number of entries in the table for refrigerants are for mixtures of gasses.

I don't think these lists are complete, but there are comparatively few substances with such low boiling points (probably no more than a few thousand that could ever be made), simply because having more than a handful of atoms will already cause the molecules to attract enough to remain as liquids or solids at non-cryogenic temperatures.