Ballet Shoes by Noel Streitfield may be perfect - very gentle, innocent story and a good read without being complicated emotionally.
Anne of Green Gables also gentle, fun, good vocab.
The Whizz Pop Chocolate Shop is great. Sequel is as well - The Chocolate Phoenix. Magic, adventurous, but not scary as Potter can be.
Meg Cabot the Princess Diaries seems really popular with lots of little girls I know. I don't know much about the series, but Disney made a film of them, so presumably they are fine!
The St Clare school stories by Enid Blyton, also the Faraway Trees, as has been mentioned by others.
The Worst Witch is a lovely series for a younger good reader.
The Holly Webb series seem twee to adults but I know 7 year old girls who are obsessed by them, so worth a try?
Howl's Moving Castle is a lovely fairytale.
Rumer Godden "The story of Holly and Ivy" - be careful though as some of her other books can be surprisingly dark.
Black Beauty - sad in parts, but unlike Charlotte's Web, the ending is happy.
I bought The Tree That Sat Down on recommendation from another poster a few years ago, and while we've not read that one yet, it's been re-released (I bought an old copy via Amazon) so presumably it has a good market! Someone else suggested The Snowball, and ditto. Both written in the 1970s when a primary aged children's story had to be innocent to pass muster. Both were remembered with passionate enthusiasm by several posters once named. So I am namechecking recs so enthusiastic I have myself been impressed enough to track the out-of-print copies down for my own kids - now they are back in print, I pass on the love!