Other than Fairy-Max, is there a variant [fairy] chess engine that is compatible with XBoard? Fairy-Max (which ships with the XBoard package) can play variant chess. Is there any other XBoard-compatible engine that also plays variant chess (and runs on Linux or *BSD)?
The XBoard Alien GUI is reputedly better suited to playing chess variants than the standard XBoard is, but that's just an observation. There are many engines that play only a few variants.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Here's a list of engines (other than Fairy-Max) that have been noted as playing a large selection of variants and working with XBoard (Linux environment being implicit):


ChessV (plays over 50 variants)
Nebiyu Alien (a score of variants tested in homepage; many additional [user defined] .ini files available as a collective package or individually)
Pulsar
Sjaak II (Glebbeek's, not de Man's)
SMIRF