I’ve used Papaly for years now as a start page. Problem is though that’s it’s slow and clunky. Right now I’m looking into BookmarkNinja to replace as I’m hoping it works better.
Another issue is having to have an account signed-in which is sometimes buggy and you need to log out and in again.
I actually haven’t seen a browser try to implement a built-in feature like this but then of course I never knew what a Collection was till I tested out Edge to check out its features.
It would be really cool if Brave had something built-in like this which could be stored locally and such.