All classes are available, but some have unique aspects within a Colossus of the Drylands campaign.
Druids
Druids in the Drylands are more equipped than many to navigate the inhospitable environment. They're familiar with the unique qualities of desert flora and fauna, and their spells and abilities reflect that.
Rangers
Many rangers in the Drylands are "lone riders" who prefer only the company of their mount and ride from outpost to outpost, never stopping for long. They're often defenders of the weak who stand up against local law enforcement when deputies push people around.
Seraphs
Many seraphs have strong relationships with their faith, either worshiping the Forgotten Gods (such as Kudamat) or the New Gods. This also affects their relationship with the use of essentia — the former utilize the crystals prolifically, while the latter may have a fraught relationship with magic. When playing a seraph, players should consider how their character feels about magic, as well as the way their character engages with their faith within the community. Many choose to become preachers, healers, and prophets of the land.
Syndicate Rogue
These rogues often operate as deputies, mining operation overseers, or members of outlaw posses. Though any of these groups might work publicly, it takes a master of charm and negotiation, as well as clandestine activity, to accomplish the organization's more covert goals.
Source · Character Creation Considerations