I've done vouchers in the past - usually $15 from Hudson's Coffee or Cold Rock Icecream. This is enough to buy a nice treat for themselves in the holidays. This year, I bought each teacher a Kikki K notebook & matching pen and had it embossed with their name (Mrs. A, Mr. S) which cost $20 on a super online sale. I try to avoid chocolates because I think that's a common gift and also alcohol as I wouldn't know what they like and some don't drink.
I always accompany the gift with a hand written card thanking them for specific things they have done throughout the year.

As a teacher - gifts are appreciated but not expected. If you really want to do something, a card (particularly from the student) with something personal about what they liked this year, is what most teachers I've talked to say they like best.

Coffee vouchers, scratches and stationery are my go to items for teachers

I bought my son's preschool teacher and educators a nice reusable shopping bag each. One that packs down really tiny to keep in a handbag. Kaisercraft had a nice selection. I didn't end up writing it in the card, but originally planned to add a tag with this from my son- 'A little something to help you, to say thank you for helping me'.

I got a nice water bottle and hand cream, I really liked this.