Time to add gen 7 and gen 8, yay. I'll include mythicals and UBs as well.
ORAS- Kyogre, Groudon, Deoxys.
SM- Cosmog, Cosmeom, Magearna, Tapu Lele, Tapu Bulu, Tapu Fini, Solgaleo (shiny available in Moon but not Sun), Lunala (shiny available in Sun but not Moon), Nihilego, Buzzwole, Pheromosa, Xurkitree, Celesteela, Kartana, Guzzlord, Marshadow.
USUM- Solgaleo (available in Ultra Moon but not Ultra Sun), Lunala (available in Ultra Sun but not Ultra Moon).
SWSH- Type: Null (so technically Silvally as well), Zacian, Zamazenta, Eternatus, Kubfu, Urshifu, Zarude.
Source
Hope this helps! :)