Worlds of this series of games and books:

Accatran
Adrantis V
Aerius
Agripinaa
Anark Zeta
Angelis
Arkhona
Armageddon
Artemis
Arthas-Moloch
Attila
Aurelia

Baal (not to be confused with Ba’al, ally of the Inisfreeans (ICVs))
Badlanding
Badab Primaris
Bakka
Bakka
Bakka Triumveron
Banish
Barbarus
Belis Corona
Bellerophon’s Fall
Besarife
Beta Anphelion IV
Betalis III
Black Reach
Brontissa

Cadia
Caliban
Calth
Carcharias
Catachan
Certus-Minor
Chaeronia
Charadon
Chemos
Cinchare
Colchis
Costeau XI
Cretacia
Cthonia
Cuyavale
Cypra Mundi
Cyrene

Damnos
Davin
Deliverance
Dolumar IV
Drazak
Dynikas V

Eidolon
Elysia
Endymion Prime
Etiamnum III
Eustis Majorus

Fenris
Flint
Footfall
Fortis Binary
Fourtheden

Galen VI
Galt
Gath Rimmon
Golgotha
Gravalax
Gryphonne III
Gryphonne IV
Gudrun

Hagia
Herodor
Honourum
Hubris
Hyades
Hydra Cordatus
Hydraphur

Ichar IV
Inwit
Istvaan III
Istvaan V
Ithaka

Jericho III

Kaeriol
Karacallia
Kaurava System
Khur
Kokytos
Knight Worlds
Kracis IV
Krieg
Kritias Secundus
Krodha
Kronus
Kulth

Lorin Alpha
Lorn V
Lucius
Lukius
Luther McIntyre IX

Maccabeus Quintus
Macragge
Maeleum
Maesa
Medusa
Medusa V
Menazoid Epsilon
Minea
Mordax Prime
Mordian
Mundus Planus
Murder (One-Forty-Twenty a.k.a Urisarach)

Necromunda
Nemesis Tessera
Neutra (Torva Minoris)
New Badab
Nikaea
Nimbosa
Nocturne
Nostramo
Nuceria

Obsidia
Ohmsworld
Olympia
Ophelia VII
Orask
Orbiana
Ornsworld

Pindarus
Plague Planet
Planet of the Sorcerers
Posul
Praetoria
Prospero
Pythos

Rahe’s Paradise
Reth
Rogar III
Rynn’s World
Ryza

Sabatine
Sabbat Worlds
Sacris
Sarosh
Sarum
Sepheris Secundus
Shaprias
Shenlong
Sicarus
Sotha
Stalynthia
Stygia-Aquilon (binary world)
Stalinvast
Stygies VIII
Sycorax

Tallarn
Tanith
Taros/T’ros
Tarsis Ultra
Tartarus
T’au
Thracian Primaris
Thrax
Titan (Moon of Saturn)
Tranquility III
Turtolsky
Typhon Primaris
Tsagualsa

Ullanor

Valhalla
Varadon
Varsavia
Vior’la
Verghast
Vilamus
Volistad
Voss Prime
Vostroya
Vivaporius
Vraks
Vyaniah

Woe
World Engine (Borsis)

Xenax
Xerxes Quintus

Yu’Kanesh

Zaebus Minoris
Zhoros

 

Details here and here.

2023/+ Updates:

Speculation:  (humans in The Imperium) population between 4,000,000,000,000,000 and 1,500,000,000,000,000,000.
At least 1,000,000 worlds.
4 quadrillion evenly distributed to 1M worlds = 4B/world
vs.
1.5 quintillion / 1M = 1,500,000,000,000/world (thus probably many/most in Space stations and ships, not on those worlds)

Still, 1.5 quintillion is 2,744.003347x less than the Inisfreean population; negligible to us.

1,000,000 planets in the Milky Way galaxy (MWG) is ~.001-.00025%.
(est. 100-400B stars and at least that many planets)

With 100B-2T galaxies in the Universe, and multiple Universes, even the Imperium of Man is negligible.

Total Annihilation‘s opening video says its war ruined 1,000,000 worlds, so maybe that was the end of the Imperium of Man; Total Annihilation may pick up where Warhammer leaves/left off.

>1,000,000 worlds in the Imperium of Man could be a 100x100x100 group of solar systems, or much smaller if multiple worlds per system
..
but is said to span the entire galaxy
..
thus controlling <1% of MWG solar-systems –bc (at least) ~100B stars make up the MWG
(actually only 1/100,000th; .001 of 1%)

Inisfree has been in Arcadia (dimension of the Fairies) for millennia by now, missing all Warhammer 40k human events.

“The Imperium of Man is home to over 1,000,000 human-settled planets scattered across over 100,000 light years of space in The Milky Way galaxy.”
Is that 100,000 LY^2? (~316×316)
^3? (~46×46×46)
Or do they mean the entire diameter of the MWG?
Either way, that is a small number compared to the hundreds of billions of stars, and trillions of planets there.
..
1,000,000 avg. out over 38,000 years = 26.31578947/yr

 

Also see:

  • Ultramarine Movie – 1080p Quality” (just keep in mind that they are brainwashed/polarized, and actually the cause of their own problems; manifesting what they assume they are subordinate/submissive/victim to, etc.)