The archaeal clusters of orthologous groups (arCOGs) Database is a curated database of clusters of genes within the archaeal domain with shared evolutionary history that can be used for the functional annotation of archaeal genomes. There have been multiple updates since the original release all of which can be found via the link.
Citations
Makarova KS, Wolf YI, Koonin EV. Archaeal Clusters of Orthologous Genes (arCOGs): An Update and Application for Analysis of Shared Features between Thermococcales, Methanococcales, and Methanobacteriales. Life (Basel) 5, 818-840 (2015).