>>96145886
Absolutely.
Archon does also those big sets with a large variety of fantasy miniatures.
If its not Army building, something like pic related would maybe also work? Pretty much all their sets include some more "traditional" fantasy creatures, and some that could easily pass as Aliens in any sci-fi setting.
The question is if its worth to buy a 50€ box if all you want is 2-3 minuatures out of 50. But sometimes they are sold as singles on ebay too.