You can adapt these based on your relationship and the occasion:
"Your support means the world to me. Thank you for seeing my potential and calling it out." buying teachers presents
"To celebrate the end of the year, we're putting together a small gift from the whole class. No pressure at all, but if you'd like to join in, we're collecting [Amount] each." "Thanks for helping me grow!" "To the best kind of teacher—thank you for everything." "Thanks for being an inspiration this school year!" What Teachers Actually Value You can adapt these based on your relationship
"Hi everyone! A few of us are coming together to get a group voucher for [Teacher's Name] to show our appreciation. If you'd like to contribute, please let me know by Friday!" please let me know by Friday!"