Congratulations!
We have just invested in a big bean bag, and it is 100% an excellent choice. The IKEA foldaway mats are also great, they get used plenty.
Trunkis have stood the test of time for a toy and for special sleepovers or travelling.
Ours have tablets because we do loads of long car journeys. Kindle fire kids version is perfect for them.
We got nooie baby monitors and we still use them to check how bad the shenanigans are on a Sunday morning so we don't have to get out of bed unless it is absolutely necessary!
Weighted blankets and night lights, sleep stuff might be helpfulic they struggle with that stuff.
Balance bikes or bikes/scooters if they don't have them can help burn off energy- ours love them and use them all the time.
A bit random but we invested in some family 365 tupperware from IKEA, it was a bit expensive but definitely worth it be ause it's all modular. Decent water bottles that they like to drink from and won't get cracked if they are dropped (ours haven't managed to break the contigo water bottles yet)
Nice lunch boxes for school maybe? I have a pet peeve with the soft lunch boxes be ause I get grossed out with how dirty they get so you can get hard shell ones too.
We got hooded bath towels, they have been great to snuggle them up and give them a big cuddle and deep pressure before bed.
A decent set of outdoor clothes- waterproof trousers and puddle suits again have served us very well, mittens sewn onto elastic like we did in the 90s again have been great.
Playdoh is always a hit- we make our own in the slow cooker because it is cheaper and I don't get as annoyed when they mush it together, but all the little squishy machines are good if they are cross and want to mash some anger out on some unsuspecting playdoh. Plus it's great for parallel play, you can just sit down and make something and they can join in or not as they want.
Beach stuff like buckets, nets and spades, a little tent, beach shoes, stuff like that.
I also got some puzzle books for me so that I wasn't on my phone at the park all the time.
If they are fussy eaters plates with dividers might be useful.
Stuff I wouldn't bother with is anything with loads of tiny bits that isn't interchangeable. So Lego, fine, hotwheels, great, Barbie, marvellous. A random car garage or dolls house that is assembled using only specific pieces of plastic tubes before being packed away again and losing the one precise bit that holds it all together, not so fine.
Controversial for an English teacher, but not too many books. We ended up buying books that dealt with the specific issues they were having and whatever interests they had as we went along. Our bookshelves were full quite quickly!
Ours also don't really vibe too well with arts and crafts. They will occasionally go for a colouring book, and stickers on the odd occasion, but they aren't really ones for drawing and painting.
We also ended up with loads and loads of teddies. Intro teddies, teddies from BPs, teddies from the court adoption day, teddies from nursery, we are drowning in them and they don't really play with them or attach much meaning to them.
Last one is jigsaws. We lost loads of bits and I just got stressed about keeping them together.