Subreddits similar to r/self

r/sex is for civil discussions about all facets of sexuality and sexual relationships. It is a sex-positive community and a safe space for people of all genders and orientations. This is (mostly) a 'serious' community - posts and comments that sidetrack discussion will be removed and may result in a ban.
https://reddit.com/r/sex/

r/promos

12k subs

https://reddit.com/r/promos/

r/IAmA

19m subs

https://reddit.com/r/IAmA/

r/TrueReddit

445k subs

A subreddit for really great, insightful articles and discussion. Please follow reddiquette, and READ THE ARTICLE before voting or discussing. Downvotes should only be used if something doesn’t contribute to intelligent discussion, not just because you disagree. Please use the report button if you see something that doesn’t belong.
https://reddit.com/r/TrueReddit/

r/scifi

1m subs

Science Fiction, or Speculative Fiction if you prefer. Fantasy too. Asimov, Bradbury, Clarke, Dick, Heinlein and other SF books. SF movies and TV shows. Fantasy stuff like Tolkien and Game of Thrones. Laser guns, space ships, and time travel. etc. Star Trek, Battlestar, Star Wars, etc.
https://reddit.com/r/scifi/

r/wikipedia

298k subs

The most interesting pages on Wikipedia.
https://reddit.com/r/wikipedia/

r/Frugal

1m subs

Frugality is the mental approach we each take when considering our resource allocations. It includes time, money, convenience, and many other factors.
https://reddit.com/r/Frugal/

r/secretsanta

129k subs

/r/secretsanta and Reddit Gifts were started in 2009 to provide a secret santa for the Reddit community. We have since expanded to many gift exchanges.
https://reddit.com/r/secretsanta/

r/atheism

2m subs

Welcome to r/atheism, the web's largest atheist forum. All topics related to atheism, agnosticism and secular living are welcome here.
https://reddit.com/r/atheism/

r/offmychest

2m subs

A mutually supportive community where deeply emotional things you can't tell people you know can be told. Whether it's long-standing baggage, happy thoughts, or recent trauma, posting it here may provide some relief. We'll listen, and if you want, we'll talk. We aim to keep this a safe space.
https://reddit.com/r/offmychest/

r/AdviceAnimals

8m subs

Reddit's Gold Mine
https://reddit.com/r/AdviceAnimals/

r/WTF

6m subs

Things that make you say "What the F*ck".
https://reddit.com/r/WTF/

r/trees

1m subs

The go-to subreddit for anything and everything cannabis. From MMJ to munchies, from nugs to news, and everything between! The casual cannabis community
https://reddit.com/r/trees/

r/firstworldproblems

236k subs

First World Problems. If it's a problem you can only have if you have money we'll feel bad for you. Then we'll feel guilty for having enough money to have the same problem.
https://reddit.com/r/firstworldproblems/

r/askscience

18m subs

Ask a science question, get a science answer.
https://reddit.com/r/askscience/

r/millionairemakers

124k subs

If a million people gave a dollar to someone, they could be a millionaire. We are an embodiment of this showerthought: https://redd.it/2mq94c Additionally, you can join our mailing list for monthly reminders at send.redditmm.com
https://reddit.com/r/millionairemakers/

r/business

501k subs

/r/business brings you the best of your business section. From tips for running a business, to pitfalls to avoid, /r/business teaches you the smart moves and helps you dodge the foolish.
https://reddit.com/r/business/

r/technology

8m subs

Subreddit dedicated to the news and discussions about the creation and use of technology and its surrounding issues.
https://reddit.com/r/technology/

r/Music

21m subs

The musical community of reddit
https://reddit.com/r/Music/

r/Fitness

7m subs

Discussion of physical fitness/exercise goals and how they can be achieved
https://reddit.com/r/Fitness/