Here are a couple of user created content subreddits I like. They fall into the general overlapping categories of making and fixing things, and taking cool pictures of clouds, plants, and *nix desktops. :)

If you prefer the new layout you can "s/old/www/g".

https://old.reddit.com/r/3Dprinting/

https://old.reddit.com/r/CLOUDS/

https://old.reddit.com/r/electronics/

https://old.reddit.com/r/KerbalSpaceProgram/

https://old.reddit.com/r/painting/

https://old.reddit.com/r/Pizza/

https://old.reddit.com/r/ramen/

https://old.reddit.com/r/retrobattlestations/

https://old.reddit.com/r/succulents/

https://old.reddit.com/r/unixporn/

https://old.reddit.com/r/vintagecomputing/

let me add

https://old.reddit.com/r/proceduralgeneration/

Wow, 16 year old me would've killed for this link in highschool. Thanks for this one!

A few more

/r/battlestations

/r/buildapc

/r/GameDeals

/r/Rainmeter

/r/diyaudio

/r/fixit

/r/TronScript

/r/AutoHotkey

/r/bookmarklets

/r/homeassistant

/r/nodered

/r/Bogleheads

/r/juststart

/r/Optionswheel

/r/qyldgang

/r/thetagang

/r/VegaGang

/r/patientgamers

/r/slavelabour

/r/Anki