Accessories go down well at that age as they're easy to take on and off. So charity shop hats, handbags, scarves etc. Plus a few fairy / witch dresses, and stuff that goes with (wand, wings, witch's hat, witch's wig etc). And some task-related stuff - Melissa and Doug does pricey but nice firefighter, doctor, astronaut sets. You could get others to contribute, perhaps?
Hats are always good! I'd wrap them all separately if they aren't getting many other things.
In our dressing up box we have : Tutus in various colours Doctors set with real stethoscope and oroscope and surgical masks etc Doctor / vet / scientist white coat Chef stuff Big hat and disguise glasses with spy kit I made up Disney princess dresses High heeled shoes Lots of things like beaded necklaces and feather boss Policemans hat High vis vests Fire helmet Hairdressers coat with FAKE scissors and hairdryer etc Builder costume and tools Big lengths of different coloured / textured fabric Swords and shields
We have hats from Wilkos which were v good value, couple of quid each iirc... one is a builders hat & I then bought a high vis waistcoat thing off amazon cheaply to go with it.... round near us I’ve seen some nice old fashioned/ medieval princess hats & Robin Hood type hats at museums/ castles if you have anywhere nearby like that with a gift shop- they seem v reasonable prices, not as ££ as ordering a full outfit
Can you get to a fabric shop? My DCs enjoyed a couple of big furry animal print offcuts and a sparkly length which were 50p each. If you literally put it all in a box, make sure it's finger trap and suffocation proof.
We have playsilks (silk scarves in different colours) which are used a lot in dress up, as well as for making dens/ doll blankets/ teddy sling, picnic rugs, theatre curtains, etc They are silly money to buy and a very satisfying and easy craft to make Fabric off cuts would be good too but the light silk is very easy to twist and tie and not at all restrictive to toddlers and little hands