I think it might be preferable to separate "Hellgates", which are portals to Hell or other bad places, with the concept of a "Nexus of All Realities" like in Man-Thing which links indiscriminately to all sorts of different dimensions and realities in a multiverse. The latter is a trope that has occurred enough times I think it deserves its own page. Just the ones I know about would include Sigil from Planescape and maybe Stephen King's Dark Tower. And I remember an old TMNT with a nexus of some kind in a subway tunnel. Plus Cynosure from Grimjack. And from webcomics there's the Portal To Many Places from Dr. McNinja, the Castle Beyond Space and Time from PS 238, the Hub from Jump Leads. I'm sure there are plenty others.
I think it might be preferable to separate "Hellgates", which are portals to Hell or other bad places, with the concept of a "Nexus of All Realities" like in Man-Thing which links indiscriminately to all sorts of different dimensions and realities in a multiverse. The latter is a trope that has occurred enough times I think it deserves its own page. Just the ones I know about would include Sigil from Planescape and maybe Stephen King's Dark Tower. And I remember an old TMNT with a nexus of some kind in a subway tunnel. Plus Cynosure from Grimjack. And from webcomics there's the Portal To Many Places from Dr. McNinja, the Castle Beyond Space and Time from PS 238, the Hub from Jump Leads. I'm sure there are plenty others.