What did kids read in the 70s and 80s?

Definitely Enid Blyton, Secret Seven, Adrian Mole

I don't think it's quite that simple unfortunately.
I read a lot as a child favourites included Roald Dahl, Enid Blighton famous five, secret 7 etc.. I loved the mysteries. Lion witch and wardrobe series, railway children, Heidi, little women. A little older 13 / 14 hitch hikers guide or lord of the rings.
My dd has read all the authors in your op and last Christmas we bought her the Narnia series. Book 1 is still sitting on her book shelf half read. I suggested we read it together as she was finding it a bit dull. Unfortunately she is right. It isn't fast paced and exciting in the way Harry Potter is, or funny like David Walliams or the wimpy kids books.
I think children's literature has moved on quite a lot from what we were used to and honestly I found it dry and slow even though I have such good memories of not being able to put it down.
The only author from my childhood which my children have loved is Roald Dahl.
I still have high hopes for hitch hikers and lord of the rings in a year or 2 though

I was totally all about the Judy Blume!
I met her 2 years ago in hay on wye And I was star struck

I loved loved maud in worst witch!!!!
Judy Blume
Danielle Steele nicked off the book shelf

The sheep pig
Danny the champion of the world and similar age pitched Dahl
Charlotte's web
Stig of the dump

Blyton, loved the 5 find outers and the adventure series and the school ones
The hobbit. Lotr in nineties!
5 children and it, railway children
Secret garden, little princess
Jennings and Derbyshire.
SVH
First three worst witch books - think the others came out later
Early Pratchett by the late 80's I think. May have been a couple of years later
Green gables series
Little house series

Class reader was always Carries bloody war. Hated it, especially after the fourth reading!

A lot of the books I read have already been mentioned but I also liked Ursula Le Guin's books, and slightly spooky things like Charlotte Sometimes and Marianne Dreams and Misty comics.

My kids loved Baby Sitters Club and Goosebumps.
I loved Enid Blyton.

Susan Cooper (especially the 'Dark Is Rising' series), Alan Garner, Tolkien, Narnia), I also loved 'A Wrinkle In Time' (by Madeleine L'Engle, I think ). I liked mostly fantasy really - couldn't be doing with any of that young teen stuff.

I loved Enid Blyton and read them all. Our English teacher hated her books and wrote to our parents telling them to ban us from reading any of her books. My parents were of the opinion of I was reading all was good.

Ooohhh forgot Virginia Andrews and Enid Blyton. Also went through the classics but 're read those Authors several times (still do with certain books now)

Mallory Towers, Famous Five, Chalet School, Nancy Drew, The Hardy Boys, Heidi, What Katy Did

Worst witch
Mr Majekeka the music teacher
The Owl who was Afraid of the Dark
Ramona Quimby
Biff and chip stories
Mrs Pepperpot

Swallows and Amazons
Black Beauty
Treasure Island
Anne of Green Gables
Little House on the Prarie
Heidi
Narnia
Little Women
Lord of the Rings/Hobbit
Terry Pratchett

So many amazing classics, I've forgotten loads. As a child I haunted the library and read a great many inappropriate books, but it didn't do me any harm. I loved any kind of science fiction from an early age.

Yep a LOT of Enid Blyton, then Judy Blume and Sweet Valley High. Then Virginia Andrews in later teens

Actually by 12 I think I was also into Daphne du Maurier - My Cousin Rachel was the first of hers I read and I was hooked 70's child btw)

Sorry x-post rat

Brian Jacques (Redwall series), Michelle Magorian (BackHome, Goodnight Mr Tom), Philippa Pearce (Tom's Midnight Garden). And I was obsessed with books about boarding schools, so Trebizon series etc.

I loved Carrie's War - your DD might like that. Can't remember who wrote it but it's about an evacuee in WW2. Also The Little Broomstick about witches- all just so well written

Oh yes, how could I forget Judy Blume?! I LOVED her books.

I loved all the Enid Blyton books: Famous Five, Mallory Towers, St Clair's. Other favourites were The Secret Garden, The Railway Children and Pollyanna, Chronicles of Narnia. Also books by Noel Streatfield and Roald Dahl (although he is stil as popular as ever!)

Chalet School, Malory Towers, St Clares, , Trebizon... there's a recurring theme for me.

Other than that, by about 12 (mid-late 80s) I gravitated towards Terry Pratchett, Tolkien, any Enid Blyton, Peter Pan, Jules Verne. Basically anything either science fiction or fantasy. I didn't much enjoy books about modern things. I liked to be able to lose myself in a different world.

Judy blume, sweet valley high,but also the little women books by Louisa m alcott which were lovely. And by 12 I was reading a lot of adult books that my mum and sister left lying around, but I wouldn't recommend that (I learnt A LOT from the Virginia Andrews books).

I read Enid Blyton, Noel Streatfeild, Anne of Green Gables, What Katy did, Little House on the Prairie and hundreds more!

As a teen in the late 70's/80's I read Lynne Reid Banks amongst others.

There are good lists of classic books though these might not be the ones they want to read