Courtiers are more support Heroes and beatsticks, not proper leader types and thus come without any Command Abilities or magic. What they do is still very important though, as of they can Resurrect Slain Models, as of second edition. Keep in mind though that they cannot set up new units, only the Ghoul Kings can do that. This is not to say your Courtiers are less important though as they can, for example, add Ghouls to a unit until it gets its Battalion Strength back. As they don't have the Monster Keyword despite appearances, they all benefit from Look Out Sir.
*'''[https://www.games-workshop.com/resources/PDF/AoS_Warscrolls/AoS_Flesh-eater_Courts_WSCards_Varghulf_Courtier.pdf Varghulf Courtier]:'''
Oddly not a monster. The Varghulf flies has a bunch of strong attacks with more if it's in melee with ten or more models and if properly supported can be pretty much unkillable. If not , it' ll die in turn 2. What this means is that you have a model that is very strong, heals D3 Wounds at the end of each combat phase where it slew any enemies and can reroll To Hit if an '''ABHORRANT''' casts a spell within 18" of him. Oh, and he can summon additional Ghouls, Horrors, and Flayers for your eviscerating pleasure.
*'''[https://www.games-workshop.com/resources/PDF/AoS_Warscrolls/AoS_Flesh-eater_Courts_WSCards_Crypt_Ghast_Courtier.pdf Crypt Ghast Courtier]:''' A teeny tiny Ghoul champion upstart. That's what he is. He has a bunch of weak attacks and is still somewhat fragile for a Hero, with 4 Wounds and a 5+ save, similar to a Grot. His real use is in resurrecting, on average, 5 Ghouls per Hero Phase (yes, that means you can heal Ghoul units back to the point where their size-bonus activates) and he makes them stronger if he personally kills an enemy. Only use this as a last resort, though, as his reviving is superb and he's too fragile to risk in melee.