Egg groups for legendary Pokémon.

[Megaron]

(I'm not sure if this should go in the Fun and Games section/whateveritis.)

I've been thinking; if legendary Pokémon 'belonged' to the Gender Unkown egg group, what would their listed groups be?
This is what I think it would be:

Spoiler

Articuno - Flying.
Zapdos - Flying.
Moltres - Flying.
Mewtwo - Humanshape, possibly Monster as well.
Mew - Fairy, possibly Ground as well.
Raikou - Ground.
Entei - Ground.
Suicune - Ground.
Lugia - Flying, Water 1.
Ho-Oh - Flying.
Celebi - Fairy, possibly Plant.
Regirock - Mineral.
Regice - Mineral.
Registeel - Mineral.
Latios - Dragon.
Latias - Dragon.
Kyogre - Water 2.
Groudon - Monster.
Rayquaza - Dragon.
Jirachi - Fairy.
Deoxys - Either Humanshape or Indeterminate.
Uxie - Fairy.
Mesprit - Fairy.
Azelf - Fairy.
Dialga - Dragon, Monster.
Palkia - Dragon, Water 1.
Giratina - Indeterminate, possibly Dragon.
Cresselia - Fairy, faint possibility of Water 1 because of it being based on a swan.
Darkrai - Indeterminate.
Phione - Fairy, Water 3.
Manaphy - Fairy, Water 3.
Heatran - Indeterminate OR Monster.
Regigigas - No clue.
Shaymin - Ground, possibly Fairy.
Arceus - Ditto OR Ground.

What's your opinion?
Fear my nerdiness.

 

[RudolphMilotic]

Both Phione and Manaphy are already in the Fairy and Water 1 Egg Groups. The "Gender Unknown" egg group actually doesn't exist within the programmation of the games; it just was a way to tell that some Pokémon who don't have a gender can still breed, like Porygon, Electrode (Mineral) or Starmie (Water 3), but only with Ditto (Ditto egg group).

Nevertheless, Latios, Latias, Cresselia and Heatran have a gender, so placing them in the "Gender Unknown" group is moot. They can't breed due to their No Eggs classification and not because of their legendary status, at least from a breeding mechanics perspective.

And why you're hypothetically placing all the "cute" event Pokémon in the Fairy group?. For me, both Mew and Shaymin don't look at all like one of those fantasy creatures; Mew should be 'Monster' and maybe 'Inderminate', Land Forme Shaymin 'Plant/Ground' and Sky Forme Shaymin 'Flying/Plant' or 'Ground/Flying'.

 

[Megaron]

Well, Bulbapedia does say the Fairy egg group is composed mainly of cute Pokémon, so I went that way for cute legends.
That part about placing them in "Gender unknown" wasn't actually implying they should be put in Genderr Unkown; it was just to put my idea clearly (or whatever).

 

[Mijzelffan]

shaymin should be fairy and plant.

 

[PDL]

shaymin should be fairy and plant.

It looks like it belongs to the Ground/Plant egg group to me...

For other legendaries, it's mostly the same as the list in the OP, except for...

Mew - Ditto: Since it is the ancestor of all Pokémon, it can theoritically breed with anyone.
Deoxys: Indeterminate
Cressilia: Indeterminate
Regigigas: Mineral since the others would be in that group as well.

I do like the idea of Heatran in the Indeterminate group.

 

[Blumey]

Sounds cool. I think you got it pretty much right

 

[TheHungryBox]

here's suggestions for the Gen 5-7 Legendaries (and Ultra Beasts):
Victini - FIeld (possibly Fairy)
Cobalion - Field
Terrakion - Field
Virizion - Field
Tornadous - Human-like (Flying in the Therian form)
Thundurus - Human-like (possibly monster in the Therain form)
Landorus - Human-like (Field in the Therian form)
Reshiram - Dragon (possibly Field)
Zekrom - Dragon, Monster
Kyurem - Dragon, Monster
Keldelo - Field
Meloetta - Human-like (maybe Fairy)
Genesect - Bug, Mineral

Xerneras - Field, Fairy
Yveltal - Flying (possibly Monster or Dragon)
Zygarde - Dragon (possibly Amorphus)
Diance - Mineral, Fairy
Hoopa - Amorphus? (that's a complicated one)
Volcanion - Monster

Type: Null - Field, Mineral
Silvally - Field, Mineral
Tapu Koko - Fairy, Human-like
Tapu Lele - Fairy, Human-like
Tapu Bulu - Fairy, Human-like
Tapu Fini - Fairy, Human-like
Cosmog - Amorphus
Cosmoem - Amorphus, Mineral
Solgaleo - Field, Mineral
Lunala - Field, Flying (or Amorphus)
Nilhilego - Amorphus
Buzzwole - Bug, Human-like
Pheromosa - Bug, Human-like
Xuritree - Amourphus
Celesteelia - Mineral
Kartana - Grass, Mineral
Guzzlord - Dragon, Monster
Poipole - Dragon, Amorphus
Naganadel - Dragon, Amorphus
Blacephalon - Amorphus
Stakataka - Mineral
Necrozma - Mineral
Ultra Necrozma - Dragon, Amorphus
Magearna - Mineral, Fairy
Marshadow - Amorphus, Human-like
Zeraora - Field, Human-like
Meltan - Mineral, Amorphus
Melmetal - Mineral, Amorphus

 

[Rocket Zigzagoon]

I could also see Heatran being in Monster/Mineral group, too. Not because of its Legendary status but its origin being based on turtles which are endangered species. Or certain extinct species.

 

[Poke Dragon]

I can see Necrozma being from the Mineral and Dragon Egg groups regardless of the form, it's really not new to expect it since we literately have two fish Pokemon who are part of the Dragon Egg group simply because they evolve into dragon-like Pokemon.