With the release of DGM, I think it's relevant to include a special filter option that would allow to filter cards associated with individual Ravnica Guild.

For example, "Orzhov guild" filter would return all cards with Haunt, Extort, and all BW cards in GPT, GTC, and DGM, including Shrieking Grotesque, Ostiary Thrull, Shadow Lance, Crime, Seek, Dutiful Thrull, and DGM split cards, which also carry the guild symbol in their rules text.