Congratulations to your friend! What a lovely idea :)
As other people have mentioned, the gift of time, clean laundry, babysitting or hot meals is amazing to be honest, but I get that you might want to give them a thing.
I would get them to double check what the child has already, and what she might want to buy herself, because some purchases are a bit of a rite of passage. Nothing quite like browsing the kids section after years of skipping it! We wanted to buy a lot of books and clothes ourselves because we hadn't done it and we wanted to.
It depends on how sentimental she is- we err on the side of practicality rather than sentimentality because our house is too small for much other stuff! Her taste might be different.
We adopted slightly younger but now have a 4 year old. I figured I would list some stuff that you might not have thought of but that we now use often enough for it to be a practical gift. We have 2 rambunctious boys, so maybe ignore some of the stuff if she has a very quiet child!
Practical stuff:
Booster cushion for sitting at the table in a pattern they like
Balance bike/scooter and helmet
Fold up crashmat from ikea - it's called plufsig
Contigo water bottles with the auto spout (great for sucking and regulation and have lasted us a year so far)
Chewellery- we needed loads
Personalised rucksacks for school
Tiny play kitchen from amazon that fits the side of our fireplace
Peanut ball
Some sort of outside toy- rocket stamper toy works well for energetic kids
Nightlight (dinosaur, unicorn stuff like that, you can get ones that are personalised)
Nooie baby camera (you can use it to talk to the kid, and ours feel reassured that we can see them).
Gro clock
Swimming towels with a hood on, goggles, swim cap if they are planning on swimming stuff
Wellies and rainsuits
Weighted blankets
Bed tent
Trunki in the character they like.
Tonie box with some tonie characters
Tablet headphones (this one is a bit controversial/a big ticket item, but if she is planning on giving a tablet maybe some accessories for it). I would recommend Bluetooth ones!
Extra tall babygate
Flashing toothbrushes
Walkie talkies
Disco ball - great for afternoon dance parties!
Lava lamp- hypnotic enough to entertain a kid for at least a few minutes!
Bath toys
Non clutter stuff:
disney subscription
spotify premium subscription
Clarks/startrite voucher for school shoes
Takeaway vouchers
National trust membership- we love ours!
Sentimental stuff:
Token for a photoshoot later on when they are settled
Footprint or handprint sets
Scrap book
Matching mummy and me jumpers (I did NOT account for how much I needed these in my life.)
Book from wonderbly- the characters can be personalised and they are quite open ended
All that being said, the honest to goodness best thing is the promise of a good meal and a non judgemental person at the end of the line in a difficult moment is the best gift.