This is a curated and forever Work In Progress list of what I consider to be the best Thief I, Thief II, and The Dark Mod fan missions. It's not definitive, and I'll continue to add entries as I revisit some missions and discover new ones. This list is obviously fairly biased toward the way I play and what I like to see explored by mission creators. You'll notice a clear lack of supernatural-themed mission, and a lot of "city romper" composed of numerous interconnected areas. The missions are also not necessarily "ghost-able". I find this level of stealth obsessive and am already abusing quicksave enough as it is. I'm more interesting in artistic direction and level design than gameplay and stealth proper. For a more definitive list, see this thread.
The two original games are household names with overall memorable campaigns. Over the course of several decades, In a similar fashion than the Quake community still do for its beloved FPS, taffers from around the world built upon those foundations and released fan missions increasingly more inspired, complex and polished, thanks to patches bringing new scripting abilities and technical overhaul to the Dark Engine.
The Dark Mod is technically unrelated to Looking Glass Studio works, albeit heavily inspired by it. The ID Tech 4 engine on which the one from The Dark Mod is based in an entirely different beast. The gameplay is similar but more subtle, a bit more low-paced and the AI smarter. The world building is not a carbon copy of Thief's one though very similar.
I still think it's relevant to group them together. I've been a huge fan of Thief's unique universe since my teen and I continue to play fan missions from each games for the same reasons : The pleasure to explore one's author artistic vision of a an endless, nameless, medieval steampunk city, vertiginous and dizzying in scale, theater of dramatic social struggles, sinister plots and all kind of secret conspiracy, which the player have to sneakily unravel while lurking in the shadow, pockets heavy with stolen loot.
Without further interruption, let's celebrate, and have some lists.
PukeyBrunster & Tannar, The Scarlet Cascabel, 2019 1
The focus of the campaign is a very well-made hotel mission. A common trope in this setting is to reflect the personality and endevors of a client through the hotel's bedroom they rent. This mission is no exception, but it manages to keep it from feeling to artificial and forced. Many secrets lie in the old building, some much darker than others. [to detail more later]
Korthak, Whispers Below the Cobblestone, 2021 2
City romper. High verticality and connectivity between the different areas, from the rooftop to the deepest cavern, below the curfewed undercity. One area is very difficult top spot and makes the third part of the mission unaccessible if not found. Very solid nonetheless
Nomadman, Intertheft, 2022 3
Reinventing the tepid Thief's Guild and its quarrel of underground crime lords into something more palatable and exciting. It manages to capture some typical Thief I atmosphere, where opulent gothic mansions patrolled by thugs are installed right next to crypts and sewer complexes.
TheDataElemental, House of The Architect, 2022 4
Borrows from the best Thief mansion missions to provide something huge in scale. Only contender in a community contest with Intertheft, it also manages to provides this unique blend of splendour, occult and medieval imagery in a bizarre mansion in which Constantine would feel right at home.
Saturnine, Rose Cottage, 2010 5
Haunted manor, but surprisingly - and to my great delight - few jumpscare-y moments. It plays almost like a point-n-click. Gorgeous looking, good level design, optional treasure hunting in the manor after the source of the haunting has been dealt with. Incredible atmosphere and story-telling.
Eternauta, Kingsbridge, 2014 6
Plagued city romper. On top of the custom assets, sounds and textures work, the striking color palette really helps making the mission memorable. It is built around the contrast bewteen the heavy use of fire-based lighting and heating sources and the overwhelming presence of the winter cold. Quite an inventive mission where the collected loot can be used to buy items to help in completing some objectives, often optional. Alternative endings can be reached by more inquisitive players.
PukeyBrunster, Morbid Curiosity, 2016 7
City romper, where the city is both on lockdown and busy celebrating a local party. Lot of custom assets and scripts, and a lot of objectives. There is an interesting contrast between the cheerful streets, full of drunk singing citizen, and the gloomy crime scenes hidden from public eyes. Trade good deeds for mysterious artefacts. Also a fun freak show twist.
DirkBogan, Compulsory Egress, 2019 8
City romper in a quarter where all the inhabitant were mysteriously and suddenly evicted. It's a Thief II fan mission with a clear Thief I vibe. Because of its dazzing maze-like architecture and bizarre urbanism, It reminds me of the city exposed through the introduction cimatic of the first game. I did not find a way to finish the mission without giving the alert, but there are people out there who managed to ghost it, so it's just a skill issue.
Beltzer, The Sister, 2019 9
The initial pitch is silly : Garrett has a sister. But it's a nonetheless gorgeous looking castle mission with very few vanilla resources. Breaking in through the guarded roofs under a bright fullmoon is peak Thief.
Random_Taffer, Marbleman, Feast of Pilgrims, 2020 10
High connectivity between areas. Great variety of settings, going from industrial areas to cathedral rooftops and luxurious estates. "Life of the Party" kind of mission during a summer night. A lot of optional objectives, hard to complete on a first run because some of the required items are hard to spot in the dark, and missing one requires to travel back into hard to access areas. The voice acting from the main character is a bit silly, but it's a pet peeve of mine and something to be expected from a fan mission, where it's hard to get some specific part right if you don't have a full team (see the incredible Circle of Stone and Shadow 2: Mission X). Nitpicking aside the mission is an impressive city romper.
RippedPhreak, Reverse Robbery, 2021 11
Linear progression based on a way forward and opening grates for backtracking. City romper, bank heist, very good level design and enough variety to keep things interesting.
Nicked, The Violent End of Duncan Malveine, 2020 12
Impressive mission focused on investigating a murder committed in a family mansion. The motive, murderer, alibis and cause of death is randomized each playthrough, and the player has the possibility to chose from where outside the manor they will start the mission. On top of the investigation job, the player have to steal a well-guarded diamond and frame someone from the mansion to cover their track.
It's a very large and well designed map, using only vanilla resources. It's heavy on patrols and guarded by numerous mechanical cameras, making the early part of a run a bit tedious.
If the player commit to complete the side-quest related to collecting a deck of metal playing cards, several secret passages will have to be found, making it easier to get around the gigantic mansion. Said cards will have to be hunted by solving cleverly written riddles.
As said above, the place is very well guarded and requires to attentively study the pattern of the patrols to not bump face-to-face with a guard at every corner. I don't like this kind of gameplay, and I'm more interested in exploring a lively map and unraveling mysteries. Fortunately the whole story and lore is involving enough to make up for the typical crowded-place FM stealth.
Children of Endeavour, The Builder's Paradise, 2020 13
Interesting rendition of what could have happened after the ending of Thief II : The concerted effort to stop Karras failed, and he is safe in his Builder's Paradise while pumping out machines to continue his genocidal work. It's a sabotage mission in a gigantic mechanist compound, with a stalking twist. You're the one being stalked. It's hard, but rewarding.
Vortex85, The Sword Of The Stones, 2022 14
Though instantly struck by the building's monumental quality, I first set this mission aside thinking it would be a basic castle mission, with as much loot as there is empty space. I pushed through it later to quickly discover that there is more than meets the eye. Getting to the top of the castle is only the beginning. Completing all the objectives requires the player to be quite inquisitive, and even more so to discover all the secrets. It's dense and well-balanced.
The Dark Mod
In construction. In the meantime, I'd say starting with the latest missions from authors Goldwell and Grayman is a good start.
Melan, Bikerdude, Talbot 2: Return to the City, 2010 15
Still very solid 12 year later (as of 2022). Great level design with multiple ways to reach an objectives, balanced stealth. No zombies, no magical bullshits, no bad writing, just a simple heist with a great atmosphere.
Melan, Talbot 3: Fiasco at Fauchard Street, 2011 16
Same vibe than Return To The City. Simple objectives, great atmosphere, very "navigable" city.
Baal, Bikerdude, Sir Talbot's Collateral, 2015 17
Another classic. Manor mission. Well designed with an interesting premise : a whole secret elevator system that can be used once electricity is back in the manor. Many secrets to uncover.