D&D 5E What’s the CR and type of all the titular named NPCs or Monsters of D&D books

[Waller]

I don’t have them all to check. I mean the entities named on the covers of D&D boioks — like Xanathar, Tasha….

Rise of Tiamat
Mordenkainen’s Tome of Foes

etc?

 

[Quickleaf]

Spoiler: Spoiler

Tiamat CR 30 fiend

Xanathar is a title, and there's been some variation, but current title-holder Zushaxx is a regular beholder CR 13 with a ring of invisibility, ring of resistance, and ring of mind shielding

Mordenkainen hasn't received a full write-up, merely being referred to as an archmage – but if you look at older versions, the character would at least have some cool magic items on top of that.

Tasha is Iggwilv the Witch Queen, a CR 20 fey, according to Wild Beyond the Witchlight. This is a new take or an evolution on the character.

 

[BookTenTiger]

I guess a Player from the Player's Handbook would be a CR 0 Commoner.

And the Dungeon Master from the Dungeon Master's Guide would be a CR 1/8 Cultist.