Reference: Commune with the Gods/Commune with Dinosaurs, Death Baron/Undead Slayer

(Skeletons, Vampires and Zombies are undead.)

(Graveborn, Shades, Spirits and Specters are undead, too?)

etc.

You kind of touched on this with your recent comment on the Commune with the Depths, but while majority of the 'Spirits' are undead, but I don't think all are. Are the Kamigawa Spirits such as Adamaro, First to Desire undead? Kind of, right? I don't recall how that mythology/flavor went exactly. How about Blinking Spirit, Bogardan Firefiend, Angelic Page, Diviner Spirit, Flame Spirit, or Dancing Scimitar? What about the various Spirit Avatars such as Deus of Calamity or Nobilis of War?

How much of an issue would it also be that new potential types would have to be included afterwards in that encompassing term? With undead I can see that reminder text getting quite long unless we trust that players are able to distinguish most types that would be included in that term and omit to mention some of them. In the worst scenarios, I could see this listing becoming something you would have to 'memorize' / or check up on constantly during / for competitive play.

You mention 'Graveborn' - I don't know what that is :/ Sounds like an alternative name for undead.

Kami are about as much undead as Angels are (kami are spirits in the same way a genius loci is - they are manifestations/incarnations of an idea/concept/object/place that never needed to be alive e. g. the Spirit of Christmas Past is something different than the ghost of someone who died last christmas (I never read the original story, but the adaptations imply there is one "ghost of a dead person" and three "manifestations of abstract concepts"; the first would be undead to me and the later would not)) - which they are IIRC implied to be on Alara. It differs from plane to plane and sometimes even within the same plane.

Graveborn are a token-only creature type featured on two cards (see Sek'Kuar, Deathkeeper). I understand them as Zombies and have previously pondered changing the tokens simply to Zombie creature tokens named Graveborn (compare Wasp tokens on The Hive).

I am not aware of any statement by WotC what Graveborn are, so maybe they are more like Thrulls. And maybe some are ready to argue Thrulls are undead or skaab are not - it's a whole mess. ^^

How about Horrors? Some of them look like they should be undead. Wraiths? Honestly just a type of Spirit like Specter as far as I can tell.

Now how I imagine this mess could be resolved despite the fact that I would personally be unhappy with: Make the reminder text correct and comprehensive for the current Standard environment - avoid printing any ambiguous cases in that Standard. Never return to it.

One important thing to mention: The way I have written the reminder text matches with other official reminder text and doesn't need to be comprehensive.

IIRC historic reminder text is also written in such a way that if they introduce a future characteristic that also makes a card historic e. g. "Cards with relic mana in their mana cost are historic." the current reminder text does not become obsolete - only incomplete - I think they did that incorrectly on some older cards, but take care now to keep this template.

The reason I mock up a reminder text for a batch word in the comment, but not use it on the card is, that my current position is it should not be done. I just wonder what they'll pick if WotC decides otherwise.

Special rsponse to one of the examples: I don't know whether Dancing Scimitar is supposed to be a blade wielded by a ghost, or more the genius/kami type of Spirit, but Haunted Guardian clearly is (according to the flavor text) a ghost of a dead wearing armor and nevertheless creature type Construct. I have strong opinions on this, but clearly the line blurs both ways in already existing official cards.

Published as mtgnexus Card of the Day 2019-07-14.