People who serve in the church?

Bishops, priests, and deacons.

Bishops may have the title of archbishop, metropolitan, and patriarch.

Priests may have the title of archpriest, protopresbyter, heiromonk, achimandrite, and hegumen.

Deacons may have the title of hierodeacan, archdeacon, or protodeacon.

The lower clergy are subdeacon, reader, and altar server. Some churches bless the cantor.

Besides that, there is the rest of the choir, and general maintenance staff. The organist.