Here are a few of mine:

Mesh / Decentralization / Blockchain

https://www.reddit.com/r/altheamesh https://www.reddit.com/r/darknetplan https://www.reddit.com/r/Rad_Decentralization https://www.reddit.com/r/zeronet https://www.reddit.com/r/CryptoTechnology https://www.reddit.com/r/ipfs https://www.reddit.com/r/Monero https://www.reddit.com/r/nanocurrency https://www.reddit.com/r/BATProject https://www.reddit.com/r/cryptocurrency

Technology / Software / Homelab

https://www.reddit.com/r/opensource https://www.reddit.com/r/buildapcsales https://www.reddit.com/r/selfhosted https://www.reddit.com/r/privacy https://www.reddit.com/r/jellyfin https://www.reddit.com/r/privacytoolsIO https://www.reddit.com/r/Futurology https://www.reddit.com/r/DarkFuturology https://www.reddit.com/r/StallmanWasRight https://www.reddit.com/r/linux https://www.reddit.com/r/netsec https://www.reddit.com/r/technology https://www.reddit.com/r/Purism https://www.reddit.com/r/GrapheneOS https://www.reddit.com/r/unixporn

Learning

https://www.reddit.com/r/Documentaries https://www.reddit.com/r/philosophy https://www.reddit.com/r/science https://www.reddit.com/r/Survival https://www.reddit.com/r/history https://www.reddit.com/r/Defense_Distributed

Lifestyle

https://www.reddit.com/r/EatCheapAndHealthy https://www.reddit.com/r/Frugal https://www.reddit.com/r/slatestarcodex https://www.reddit.com/r/GetMotivated https://www.reddit.com/r/malelifestyle https://www.reddit.com/r/travel https://www.reddit.com/r/Stoicism https://www.reddit.com/r/frugalmalefashion https://www.reddit.com/r/homestead https://www.reddit.com/r/gardening https://www.reddit.com/r/CampingandHiking https://www.reddit.com/r/books

Gaming

https://www.reddit.com/r/ArenaFPS https://www.reddit.com/r/localmultiplayergames https://www.reddit.com/r/GameDeals https://www.reddit.com/r/emulation https://www.reddit.com/r/lanparty https://www.reddit.com/r/linux_gaming https://www.reddit.com/r/pcgaming https://www.reddit.com/r/ShouldIbuythisgame/ https://www.reddit.com/r/GameDeals/

News

https://www.reddit.com/r/news https://www.reddit.com/r/worldnews https://www.reddit.com/r/antiwar https://www.reddit.com/r/EndlessWar https://www.reddit.com/r/evolutionReddit https://www.reddit.com/r/WikiLeaks https://www.reddit.com/r/neutralnews https://www.reddit.com/r/qualitynews https://www.reddit.com/r/UpliftingNews

Liberty

https://www.reddit.com/r/LibertarianPartyUSA https://www.reddit.com/r/ThoughtfulLibertarian https://www.reddit.com/r/GoldandBlack https://www.reddit.com/r/Rational_Liberty https://www.reddit.com/r/YourTaxDollarsAtWork

Politics

https://www.reddit.com/r/NeutralPolitics https://www.reddit.com/r/PoliticalDiscussion https://www.reddit.com/r/TrueReddit https://www.reddit.com/r/StopBeingEvil

VR

https://www.reddit.com/r/Vive https://www.reddit.com/r/oculus https://www.reddit.com/r/virtualreality https://www.reddit.com/r/SteamVR

Music

https://www.reddit.com/r/listentothis https://www.reddit.com/r/hiphopheads https://www.reddit.com/r/electronicmusic https://www.reddit.com/r/deephouse/ https://www.reddit.com/r/DnB/

Pictures

https://www.reddit.com/r/ImaginaryTechnology https://www.reddit.com/r/Cyberpunk https://www.reddit.com/r/mildlyinteresting https://www.reddit.com/r/OldSchoolCool https://www.reddit.com/r/Art https://www.reddit.com/r/interestingasfuck https://www.reddit.com/r/oddlysatisfying https://www.reddit.com/r/woahdude https://www.reddit.com/r/NatureIsFuckingLit https://www.reddit.com/r/itookapicture https://www.reddit.com/r/HistoryPorn https://www.reddit.com/r/comics https://www.reddit.com/r/urbanexploration https://www.reddit.com/r/AbandonedPorn https://www.reddit.com/r/wallpaper https://www.reddit.com/r/RoomPorn https://www.reddit.com/r/CozyPlaces https://www.reddit.com/r/ExposurePorn

Piracy

https://www.reddit.com/r/ttvreborn https://www.reddit.com/r/trackers https://www.reddit.com/r/usenet https://www.reddit.com/r/Addons4Kodi https://www.reddit.com/r/ApksApps