Galactus (Marvel)

I know the title main antagonist in Marvel and DC Comics is shared by their most evil and impactful villains (Thanos, Red Skull, Doctor Doom, Galactus)/(Darkseid, Lex Luthor, Joker, Sinestro), but is there any way to determine character(s) who could be "Secondary Antagonists" of the verses? Or are they just too expansive to do so?

January Kun Lan

February Glados

March Kefka Palazzo

April Hannibal Lecter

May Joker Court of Owls Magpie Livewire Lex Luthor and Catwoman

June Doctor Doom Apocalypse Magneto Green Goblin Galactus Thanos and Gorr The God Butcher

July Bowser

August Heihachi Mishima

September Unicron

October Black Hat Dr Flug and Demencia From Villainous

November Miraak

December Grendel