We have a lot of threads that are de facto combatfag, or storyfag, so I think explorefag games are an important topic to have some focus on. Interesting and cool enough that it deserves some big essays and effort posts, to get some of that famous Codex analysis. At the moment, I think the thread is getting lost in the big picture, because we are suggesting everything from Metroidvania to turn-based dungeon crawler (which is correct, but also non-specific). Perhaps we should identify some specific types of game, broken into specific catagories or genres?
1). Grid Dungeon Crawlers:
I would suggest that grid-dungeon-crawlers are a big subset. Out of the two progenitors of modern RPGs, Ultima and Wizardry, Wizardry is the origin of this entire lineage. I came across a relatively mainstream video the other day arguing for the colossal influence of Wizardry, for a reminder what everything from Dark Souls to Megami Tensei to Pokemon to Doom owes to Wizardry:
First person really pulls you inside the world. Also there is that sort of lonely isolated atmosphere of being left to overcome challenges without much of a narrative, almost like some sort of surreal medieval trial. The sort of situation where you imagine a higher power places you into a labyrinth to test you (miles of corridors are fantastical or surreal in themselves, yet feel somehow realistic and appropriate). I remember there was a show on British children's TV, called Knightmare, where contestants were inserted into a virtual dungeon, via old fashion animation. There was this old school feeling of some surreal wizard setting challenges and testing your courage through physical challenges and riddles:
The plain walls, the unknown passages leading away, all conjure this feeling of a place full of hidden depths. Tzeentch himself might craft something similar. My first experience with a dungeon crawler was probably a game from 1994, since I'm not really old enough to have been around when stuff like Wizardry 1: Proving Grounds of the Mad Overlord was developed. I came across an early Epic Games title called Ancients II: Approaching Evil, which wasn't very good, but even so pulled me in. Additionally, people who owned Microsoft Encarta 95 back then might remember that there was a kind of primative dungeon crawler built in called Mindmaze, where you progressed by answering encyclopedia questions.
So that's the appeal, as best as I can articulate it. You really want to see every room and fill out everything. It's the explorefag impulse at almost it's purest. Lonely isolated exploration of something that seems to perhaps have symbolic unplumbed psychological depths, a surreal series of mysterious corridors. I wish more people played this type of game, so it had more games. I wish more were developed. I guess they must probably look primative from screenshots, to the majority of nomie gamers, but are actually really vicerally addictive when you play them (and when they are done right). There
was a big post or two that contained a list of first-person dungeon crawlers, so I won't name every one.
The recent examples of the genre have come more from Japan, who still develop Wizardry series games, as well as copycats such as Stranger of Sword City, plus long running franchises like Shin Megami Tensei: Strange Journey, and the Etrian Odyssey series. In the West, real-time grid dungeon crawler Legend of Grimrock 1 & 2 were fantastic, plus other exist such as Operencia, Vaporum, and of course Grimoire.
2). First Person / Third Person Free Roam Dungeon Crawlers:
Also in that same lineage, you have the free roaming RPGs, like Ultima Underworld, early Elder Scrolls, and King's Field. King's Field and Shadow Tower, by From Software, are particualrily atmospheric, as seen in this video of the un-localised Shadow Tower: Abyss:
Essentially, these are similar to the real-time combat grid dungeon crawlers, except they allow free look, making them somewhat closer to a first person shooter. In this lineage, you have stuff like Morrowind, Arx Fatalis (re-mastered in the Arx Libertatis mod), System Shock, plus since they came from the tradition of King's Field, you could probably place Souls-like games here too. Demon's Souls, Dark Souls 1, 2, 3 and Elden Ring. Our hopes are pinned on Monomyth for a modern classic of this genre. I wish that game all the best.
3). Boomer First-Person Shooters:
As noted previously on the Codex, boomer shooters sometimes make better fantasy games than actual RPGs, capturing that sense of isolated exploration of a dungeon. I mean half of them are actually set in a dark fantasy hell world. Doom is about a demonic invasion of Earth and Mars through portals from hell. Heretic and Hexen are dark fantasy. Quake 1 is dark fantasy. For the sake of catagorisation, you can place things like Thief here.
In terms of exploration, I would say Doom 1, Doom 2, Quake 1, Blood, Heretic, Hexen, etc, all the classics, are actually great for their level design and dungeon crawling exploration. After all, just like more explicit adventure games, you are finding keys to open new areas, hidden doors, switches, obscure passages, etc. Star Wars: Dark Forces is an exceptional example. There are secret areas galore in Star Wars: Dark Forces 2 - Jedi Knight too.
4). Metroidvania
Some of the best games ever programmed by human hands. Perhaps testament to how good exploration feels as a mechanic. Fundamentally Super Metroid, or Castlevania: Symphony of the Night, or the Gameboy Advance Metroids and Castlevanias, are dungeon crawlers. You are after all entering different rooms and clearing them at leisure. Exploring a castle, and filling out a juicy glorious overworld map; something irresistable to an explorefag.
There are 3D Metroidvania games. Stuff like Jedi: Fallen Order. They also have big dynamic overworld maps, and abilities that open new areas through backtracking. Incidentally, for the love of god, play Metroid games blind. Many of them will hint where there might be an undiscovered route suffieciently enough through their map showing a false wall, or locked door, or whatever. The whole point is discovery, so to know where a secret is, or how to get it, completely eliminates most of the point in playing them. Relax and take your time.
5). Survival Horror Adventure Games:
Everything above probably fits into the Ur-Genre of adventure game, whether RPG or otherwise, they all consist of progressing through rooms, finding key items, unlocking new routes. Opening a room with a key, to find more key objects, to progress more, is the fundamental of the adventure game. Point-and-click adventure games can be explorefag. However early Resident Evil type games, perhaps Alone in the Dark before them too, are great examples of adventure games, and
Survival Horror is more of a marketing label.
Actually Resident Evil 1 is so damn addictive because it is a relatively gentle explorefag game, the horror is secondary I would argue, more of a theme. There is no real time pressure, you can explore them at leisure and slowly expand the safe zone into more and more rooms. The famous key item puzzles, like slotting an old emblem into a desk, to open a hidden drawer are pure explorefag adventure game key item puzzles. The Resident Evil 2, and Resident Evil 0, also fit this paradigm. As does Dino Crisis 1. From Resident Evil 3 and Dino Crisis 2 onward, they started becoming more about action, with less intricate exploration. The Fatal Frame series and others are somewhat so, but less successfully, as the rooms are less interesting. You also have stuff like From Software developed Kuon, and lesser known titles like Haunting Ground, Rule of Rose, Martian Gothic and Deep Fear.
Like getting the next Gridmonger release out, for instance 
