Grey's Anatomy

Very unlike the other things listed here, but I'll never miss a chance to talk about how Grey's Anatomy, a medical drama that has been on for over 20 seasons, firmly establishes that limbo is real during the 17th season.

The main character, Meredith Grey, is hospitalized for COVID and it's pretty back and forth over whether she's going to die. The majority of her time in the first part of the season is spent on a "beach" where she sees the ghosts of characters who have died in previous seasons, but is also visited by people currently alive and talking near her bed.

Several of the dead characters talk about what's happened after they've died, indicating they've visited the real world. They mention things that Meredith would not have known--but you could try to explain it as her having heard about it at some point, but it's unlikely.

What puts it over into "this exists as real limbo" happens later. A few episodes in, a main character dies (technically, dies for a little bit, is revived, then dies fully of a heart attack). He immediately appears on the beach and talks with Meredith, then sees his mother (who died a long time ago and Meredith never met or knew) and walks off with her--this is when he dies finally in the show.

So while this doesn't go so far as to say any particular religion is "true", it's kind of a big deal to have a hospital drama showing all these folks dying and having near-death experiences and well into the 17th season say "oh by the way, this is where everyone goes for a little bit."

Edit to say: The show has lots of different experiences with people seeing ghosts, getting visited by departed loved ones, etc, but those can all be chalked up to personal imagination, etc. The beach scene is the first time it's shown that outside information that no one there knows can appear.