Hello, i am part of the french testing team of Pokemon Sword Shield (to look for bugs and other problems) and i have some informations for you guys, can't reveal too much on the story so i'm gonna talk about the evolutions of the starters Pokemon (sorry if my english is bad, i'm still learning as of today).

When evolving, Grookey looks like a big angry silverback gorilla (kinda reminds me of that panda Pokemon from X/Y), brownish with a bit of green in color and he hold a big wood log that he use to hit his belly that looks like a drum (looks really cool btw, this is a great design). Learn Wood Hammer when evolving, he also get the Dark type

Scorbunny looks very slender and more feminine than the other twos, become red and black, really big folded ears and has burning foots. Think of a Blaziken rabbit

Sobble is probably my favorite of the bunch, some parts of his body are invisible and he looks far more menacing, have a frill running down his back and looks like a mix between a dragon and a chameleon. He also have some poison glands on his cheeks like these venomous toads (of course he is part poison type).

The starters can be Gigantamaxed.

I have seen some new Pokemon too but they aren't many of them and i haven't finished the whole game yet, you encounter a lot of older Pokemon like in Sun Moon. There is a stick bug (got that one very early in the game), ice type leopard, dachshund (the corgi evolution), fountain elephant, strange cyclops castle and a hammerhead shark with an anchor like head.

Too tired to write more but i can answer to some questions.