I have a recurring theme in dreams where I'll be in my home (either my current apartment, a place I've lived in the past, or some imagined house or apartment, and I'll discover whole new rooms -- sometimes entire wings of houses or apartments that are going unused. They may be empty and full of cobwebs, or fully furnished and clean depending on the dream. The weird thing is that in every one of these dreams, when I discover the new space it's as if I already knew about it and had forgotten; I'll find myself thinking things, "Why hadn't I been using these rooms, all this time?" or "How could I have forgotten this was here?"
YES! I've had a similiar type of dream for decades! In my case, it always starts with that one room in my "home" that I never really paid much attention to, or spent much time in. Usually I'll go in that room and wonder why I never really went into that room. There will be a door or two that leads into new room after new room, and I'm usually thinking "Why did I never do this before?"
As for recurring elements....I used to have a fairly expansive recurring dream geography. I once thought about mapping it out, but it became hard to reconcile certain locations because in my dreams I associate them with one of the four cardinal directions. Oddly enough, I don't recall any locales being associated with "south".
The most recurring locale these days, is a huge stairway. Now this stairway is nothing fancy or remarkable, and usually it's just....there. I couldn't tell you about whatever structure houses it. It's always different. Anyway, the stairway..... It's like something you'd have probably seen in PS1 Tomb Raider, now that I think about it. Lots of right angles, the steps themselves are large and wide, but not tall. The walls are brown stone, with some kind of paneled design I would call "Aztec-esque" because I don't really know what authentic Aztec design would look like. And there might be torches evenly spaced out every so often, it's lit up as if there were .
Anyway, every once in a while this stairway might go up. More often than not, it goes down. The thing is, I can't say how far. In this, the waking world, no term for it really works. I could say "one, two or ten stories" but that doesn't feel right. Neither does "infinity". When I'm in the dream, the best I can describe my notion of how deep it is, is a feeling of "descending into unknowable depths". There's an air of strange mystery the deeper one goes. A feeling of remoteness and a certain increasing....darkness or fading. It's hard to tell on that one. But I'm never scared, or whatever feelings of fear I have are also tinged with the excitement of descending into the mysterious unknown. Usually I'll get to some depth and get the sense that I need to get back. Occasionally these stairs may let out into a "level" or "floor", but that's very rare. Usually it's just a seemingly never ending staircase.
And that's how that usually goes. Until the other night. I had that same dream, and I was excited to be running down those stairs, into mysterious depths. I descended and as I turned the first corner, the stairs were dark as pitch, and on the walls there were bump like protrusions with glowing purple circular areas a couple inches in diameter. The glow from these was enough for me to see the other protrusions by how they blocked the glow of these purple areas on other protrusions, but not enough to really illuminate the blackness. I think I went down a flight and as far as I could tell, it was the same going forward. I was overtaken with an uneasy sense that the place had been infected by something alien and unknowable. Not sure what happened next, probably went back up and woke up.
That dream stuck with me all day, it was so weird and out of the norm. Before I had this dream, I wanted to start recording when I visited this locale, so it was weird that the first dream after this had this element. Sometimes locales in my dreams change and have a forward sense of progress. This is probably because I grew up in a huge forest area, but the forest is largely gone thanks to a massive influx of development over the last twenty years. So certain dream locales have reflected that change.