Subreddits similar to r/self

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/TrueReddit

439k 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/promos

12k subs

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

r/sex

1m subs

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/wikipedia

285k subs

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

r/secretsanta

128k 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/IAmA

19m subs

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

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/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/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/firstworldproblems

228k 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/cringepics

1m subs

An offshoot of /r/cringe, for those images that depict an awkward or embarrassing situation.
https://reddit.com/r/cringepics/

r/entertainment

1m subs

For news and discussion of the entertainment industry.
https://reddit.com/r/entertainment/

r/business

495k 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/AdviceAnimals

8m subs

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

r/askscience

18m subs

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

r/WTF

6m subs

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

r/casualiama

175k subs

The casual version of /r/IAmA. Anyone's welcome to host or participate in an AMA. Topics may involve anything from ordinary to extraordinary subject matter. The environment is relaxed, we just ask that you have fun!
https://reddit.com/r/casualiama/

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/MensRights

230k subs

At the most basic level, men's rights are the legal rights that are granted to men. However, any issue that pertains to men's relationship to society is also a topic suitable for this subreddit. Men's rights are influenced by the way men are perceived by others. There is the issue of language which can denigrate or elevate. The forces that oppose men's rights are also a topic for discussion. r/MensRights has been here since March 19, 2008.
https://reddit.com/r/MensRights/