Demonology
During the course of the series, Strange and the gang face a number of demons. Along with the ones we see, there's a great list in Strange's possession, compiled by a medieval Pope...

Strange's List

Azal
Baalberrith
Asmodeus
Lillith
Banberkak
Asmora
Satan
Devil (The)
Old Nick
Set
Baal
Loki
Abracak
Evil One (The)
Krampus
Infernal One
Appollyon
Asemedal
Gear
Milrah
Moloch
Verner
Arakne
Demons from the series:

-Azal
-Zoxim
-Kwazami
-Kaa-Jinn
-Costa Burra
-The Banshee
-The Milan Incubi
-Dubik
-Asmoth
-Joey