Birthday idea

It's not really a "must" I guess? But if you want to, look into functional and practical things - most people would avoid snacks/food items. Generally, don't give others what you wouldn't want to receive - maybe practical items like wet bags, small colouring sets etc? You can also check with the centre because they usually have general guidelines as well, and remember that the cake (if you're getting one) usually has to be halal certified! Meaning, no home bakers, no bakeries with certification :)

How about a book? I remember doing the same when my kids turned two. Popular has this series of cute books for pretty cheap that have bright pics and easy words that parents can read to their toddlers 😊 Crayons or playdough are also nice is goodie bags.

Stationery set - colour pencils, pencil cases, colouring/activity book. U can get some really cute ones from daiso and pack them in a nice gift/cartoon bag.

No chocolates no sweets please. Ended up I ate everything myself. Small uht milk, juice or toddler's snacks/biscuits ok.

Qoo10 got lotsa nice options as well! Wooden jigsaw, flashing watches, stickers and more!

Chocolate Chewy candies Cookies Some stickers Or those stick on tattoes

I gave peppa pig whistles to all the kids in my daughters school

I gave balloons to the kids and they love it!