Rather late with these ideas, but when my children were small we did a few class presents.
took some organising, but one year each child gave me a hand print in their favourite colour, with a little message on the back, I bought a cheap length of ribbon and some balloons then on the last day one of the mums who worked in the school (pta I think) stuck this round the teachers desk with balloons round the class room. The teacher loved it, cost little more than time , took a lot to arrange though.
another year, apparently the teacher was really into art, so a group of us, clubbed together and bought tubs of special paint, pads of paper charcoal I forget exactly what, and each child wrapped an item up, so all together a lovely present.
the best one though, and again took some arrangements, and involved the head teacher 😂, and it helped the mother of a child was a class support on the day. Each child bought in an item of food/drinks. At break time the teacher was on playground duty, so the children decorated the class room, and spread out the food for a party. I think the teacher was probably in on the act but was very happy with the whole thing, I made a big thankyou cake which was shared out. It’s difficult in this day and age I know with allergies etc, but still doable, the cake I made was gluten and lactose free just in case