I know this is (almost hopelessly) subjective, but can you (or others) recommend a few? (I'm a reddit newb and my feed resembles a mainstream news website).
Check out DepthHub: https://www.reddit.com/user/Lapper/m/depthhub/
It's a "multireddit", an amalgamation of multiple subreddits, a feature that Reddit as a company no longer seems to care about.
From the description:
"DepthHub gathers the best in-depth submissions and discussion on Reddit. You can use the DepthHub as an alternative front page with high quality discussion and inquiry. "
I used to visit it pretty much every day, back when third-party apps were allowed.
Hard disagree. Strict and heavy moderation is the only way to keep any discussion informative. It requires competent moderators, and there will be bad calls by the mods, but overall the alternatives are far worse.
The strictest moderation there is can be found in high quality academic publishing. You are allowed to publish only if what you say has high value, and is said in the proper way. Can't get your Flat Earth Quarterly published in Nature, and we're all better for it.
Their intention is good trying to keep out blatant spam and misinformation. Being confidently incorrect is basically a running joke on the rest of Reddit. But they could be about 75 percent as draconian as they are and still be fine.
That said, I'd be careful saying the sub can't be "trusted." It's annoying but when you do get an answer it's generally sourced and credible. As opposed to the unadulterated bullshit I've seen on the rest of the site regarding basically anything I have professional experience and/or formal training in.
Don't go to reddit for the sake of going to reddit. If you don't have a specific content area that you want to engage with, just getting involved in the reddit universe is going to be a bad experience.
EDIT: Also, the way I make Reddit useful to me is I change the default sorting for subreddits from Hot to Top > Monthly, and also disable content recommendations. It'll shows less content and Reddit will sometimes say "No more content right now", which is great.
If you're a college sports fan, /r/cfb, /r/collegebasketball, and /r/collegebaseball are excellent. The first two are large subreddits, but their mods absolutely stay on top of things. Not just clearing out spam and off-topic discussion, but also posting "official" game threads and post-game summaries so you don't have dozens of "Auburn defeats Alabama 34-28" posts clogging up the front page.
I don't use reddit for any real news, I just use it for hobbies/interests. Using reddit for news is a terrible idea for all the content farming and spam trash that this post is talking about. That would be like getting your news from just random people shouting on the side of the street.
So the hobbies/games I'm currently playing are subreddits I subscribe to and actively browse. Games like Anno 1800, Cities Skylines, and Manor Lords. All 3 have very active and passionate community members that are constantly posting high quality content around inspiration for builds, tips and tricks, community update news, patch discussions, mods, etc. etc.
If you want more silly subreddits not related to hobbies, it depends on what your humor is. Here is a wide range of options: r/AnimalsBeingBros, r/ActLikeYouBelong, r/softwaregore, r/raspberry_pi, r/lockpicking, r/FellowKids, r/dogswithjobs, r/BirdsArentReal, r/BreadStapledToTrees - subreddits that are related around hobbies or niche humor will make you love reddit.
Again, tl;dr, reddit is not the place for real life news. If you don't use it for that, you'll find yourself enjoying the website a ton more.
For the reddit and fashion newbs, I'll add r/malefashionadvice too... I mean, even if you never buy any of the expensive stuff on there, it's good just to browse the outfits people put together to get ideas about the types of things you can buy, colors, materials, accessories and how they can go together.