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]:''' The most versatile of all the courtiers - The Varghulf flies, has a bunch of strong attacks with more if it's in melee with ten or more models. This courtier is at it's best supporting your knights and serfs against chaff and mass battleline - with the aforementioned attacks bonus, Feed on Dark Magic, and Feeding Frenzy (not to mention artifacts to bump up it's attack potential), you are looking at an excellent battleline buster. Don't let him get into combat with tough hammer units or heavy hitting monsters - 8 wounds and a 5+/6++ save goes far too quickly. It 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 (Feed on Dark Magic). Oh, and unlike other courtiers, he can muster Flayers, Horrors and Ghouls. An excellent summoning choice - summon it in near units in combat at the table edge, in range for Feeding Frenzy, or place it range to support mass Ghouls - a very versatile part of the FEC army.
*'''[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.