At first I read "would not like to see replicated" and I almost got upset, haha.
For me:
Fountain pens
Communities for different countries/regions or different language-speakers - on Reddit, I often lurked /r/de, /r/Philippines, etc.
Mechanical keyboards
Woodworking
Oddly satisfying
Star Trek
Battlestations
I definitely second BIFL, Antiwork, and different communities for U.S. states, as I don't often get to connect with other people from Texas on the Fediverse.
hooray my first federated platform comment, spent over a decade on Reddit and happy something else looks to be growing big enough to be a viable alternative.
I tend to love long form text based subs. Ones I particularly enjoy where I can't currently scratch their respective itch anywhere else on the Internet:
/r/changemyview
/r/bestofredditorupdates
/r/legaladvice (mainly for the (/r/bestoflegaladvice goodies)
/r/bestof
/r/maliciouscompliance
/r/prorevenge
/r/amitheasshole
and all of the /r/talesfrom[profession] subs
yeah I know half of these are often glorified fiction writing subs but I enjoy the stories regardless
r/HobbyDrama. Fantastic reading material when you're bored. I actually still have a backlog of saved posts on Reddit that I want to get through from there (preferably sooner rather than later...).
My niche hobby and snark communities, like AmericanGirl, FundieSnarkUncensored, DuggarsSnark, and HobbyDrama. I hope to see them resurrected elsewhere with just as good of moderation and communities as they had on Reddit. I know a lot of websites say they don't want drama but a well-moderated drama community is a public service that keeps fights contained.
Kinda dumb but some of the "obscure humor" (for a lack of a better term) subreddits I kinda miss, like r/comedyheaven, r/skamteboard, r/oldpeoplefacebook, etc. The meme communities I've found on the fediverse, while totally fine, don't really scratch the same itch for me lol.
I really wish something like /r/Fitness or /r/Bodyweightfitness could gain traction on here! I miss the daily question threads and discussions about exercises, techniques, routines and things like that.
I miss the r/Aerials subreddit. It was a niche for Aerial arts, like trapeze, silks etc. I would do it but I don't know how. That's the one I miss the most really, since the community is quite small as is, and where I live there's no community at all. I just made another account on Reddit for it a couple of weeks ago.
Probably niche, but /r/skyrimmods. Nexus is a toxic hellhole, but that sub was relatively chill (although had the occasional bit of drama, admittedly).
I'll miss all the "spooky" communities, they are what brought me to Reddit in the first place way (way, way...) back in the day. Nosleep, creepy, aliens, thetruthishere, etc. There's lots of them, of varying quality these days but I regularly enjoyed the discussions and theorizing over the years.
Shout out to unresolved mysteries, that was a long term favorite of mine. At its best it was a respectful and helpful community of true crime researchers working to bring attention to cases. I am truly fascinated in evaluations of cases of misadventure, as well.
I might miss the movie discussions most, though. I love nothing more than picking apart an interesting story and getting under the obvious themes. I would regularly go directly to the official movie discussion threads after watching something I enjoyed, then search posts about it as well. I hope to find others here with the same interest because I'm sure that is something that can continue in the fediverse.
The niche I haven't found on Lemmy yet is coffee – we don't need to replicate a subreddit for every brew method, but I'd love to have a general community for coffee bean reviews and brewing tips.
I want to know what do you guys think of national/local subreddits? I found it pretty interesting to see the different national subs on Reddit like the German one or the swedish one or the french one, I found that my own nation's sub would sometimes give me information about something before it hit the local news.
twobestfriendsplay, batmanarkham, hydrohomies, me_irl, adhdmeme, all the LoL subs, casual conversation, whowouldwin, repectthreads, handful of specific game subs.
I feel like there's a lack of communities dedicated to specific games. Sure, I can see communities for Pokemon and Zelda right now, albeit on lemmy.ml
But somehow, we don't have any major Minecraft communities? I liked the subreddits for modded Minecraft and Hermitcraft. Apart from that, the Terraria sub had its moments as well.
I’d quite like an electronics interest community with decent activity, especially if there’s some proper greybeards in it who can help me with building valve/tube audio gear.
bodyweightfitness - it was a great community, but I don't know if it is a great fit here. The community was really supportive of people working on their form for movements and offered great critique without being mean, so that would fit, but it is very fitness focussed and I don't know if that is a good fit.
keto/carnivore/zerocarb/ketoscience - this was a set of communities all centered around the dissemination of information on very low carb eating, low enough to ensure ketosis rather than glucosis for energy. It is interesting to look at the resources they had and what sorts of problems you could solve by searching, but without that long term backlog of other people's problems it would be hard to start up again. Maybe also a single community rather than 4 or more, but I don't know.