What’s the British equivalent of “Friends”?

How about "The Office"? The original I mean, rather than that knockoff.

Peep Show.

Black books, I guess 

I'd highly recommend Would I Lie To You. It's just celebrities telling stories about their real lives that may or may not be true. Benefits of that format are 1.) the vocabulary is very well rounded and varied, because the stories could be about anything, and 2.) it's real conversation, not scripted, so it's completely accurate to how people actually speak. And of course the bonus is that it's absolutely gut-bustingly hilarious. You can find hours and hours of it on YouTube. I'd highly recommend looking up some of Bob Mortimer's episodes.

Why has nobody said Coupling?

If you want the 'ultimate challenge' then you need to see Auf Wiedersehen Pet, from 1982. Every difficult accent in English, all in one show. It's funny too.

Try “Traitors” for reality TV. Often the contestants do have a lot of varying accents and are from different backgrounds, but none too strong that I think you’d struggle.

If you want actual everyday language, not something scripted, try Taskmaster, or Mock the Week, or QI, or 8 out of 10 Cats Does Countdown. The British panel comedy shows are a goldmine.

Only Fools and Horses

Cold Feet

The Young Ones?

The inbetweeners

Chums!

The Inbetweeners

Coupling

Coupling

2 pints of lager.

Taskmaster

I ?think? the American show "Friends" was at least loosely based on the UK show "Coupling" - similar premise and format.

2 Pints Of Lager And A Packet Of Crisps

As an american child I picked up tons of British slang by watching top gear

Not like for like friends clone but ‘This Country’ will help your British English no end, with the bonus of not being London centric. Otherwise ‘Cold Feet’, which is ‘Friends’ but for old English people.

For reality shows 'the traitors'

It's an older show, but Spaced is brilliant. Edgar Wright, Sean Pegg, and Nick Frost before they did their Cornetto trilogy.

I know it's not exactly OP's question, but if you're looking for everyday language, you might consider British standup comedians or comedy skit shows. I'm thinking Michael McIntyre (very popular) and, in another style completely, Little Britain.

The Lord of the Rings Trilogy. Best friends ever

Not like friends, but would highly recommend Peep Show or the Inbetweeners

Coupling, without a doubt

Coupling. I think this got an American version made, but unlike the office, the American version is garbage. The original British version of Coupling is great.

Mate and lad

Peep show, miranda, it crowd, not going out, inbetweeners, Friday night dinner, the office, fleabag, outnumbered

Here’s a Brit playing some Geoguessr! He also has other interesting videos on the channel 👍👍 It’s a video made for learners so he speaks slowly and clearly https://youtu.be/ExaPEoAiBkc?si=CDO9jDozZ60bYLlT

Taskmaster. Depending on what country you're in, you should be able to find it on Youtube.

English ‘Traitors’ is good. You can get the first two seasons on Netflix. ‘Great British Bake Off’ too, also on Netflix.

try out the UK version of The Office

I'd recommend IT Crowd, not particularly long but it's a classic. All our decent ones are kinda old now that I think about them.. we did make a Friends version called 'Coupling' though I've never seen it. If you like contest type reality then Bake Off is the obvious one, there's a Pottery Throwdown, Sewing Bee, Landscape/Portrait Artist, there's one about woodworking but I forgot the name. They'll have a good mix of accents

Gavin and Stacey is probably an equivalent? It’s a very good way to learn the different accents, dialects and attitudes towards them anyway.

Philomena Cunk's documentary series and interviews