I used to be one so I am aiming to start the definitive thread. Other ideas welcome, please.
(i) If in doubt - wine.
(ii) Teachers will never know if you don't give a gift.
Honestly. I've had fab presents over the years, not necessarily expensive either. The best IMO being a beautiful bottle full of oil and herbs but I have no recollection of who gave it to me. The end of term is like that. The teacher will hardly be ticking off on a class list who gave what. Chances are they will be sick of doing it given that end-of-term assessments will have just taken place.
I feel bad about it but it happens. It's chaos and our priorities really are preparing the children for the next stage and getting ready for the next one so we can seem ungrateful sometimes. We don't mean to be but we do usually write each child a card and give a little present back. No need for endless to and fro wrt thank you letters.
(iii) Teachers appreciate friendly, understanding and approachable parents more than anything. That really is the gift that keeps on giving especially when we see you again with siblings. We love that.
So there is it. Don't worry if you have too much on. Rest assured that if you're the thoughtful gift-giving sort then your child's teacher will adore you anyway and will probably attribute that bottle of Chablis to you in any case 