I am familiar with " at the end" and " in the end" constructions, but I have found in "English Grammar in Use" book, the following sentences that contain "on the end":
Question tags are mini-questions that we often put on the end of a sentence in spoken English.
Put a question tag on the end of these sentences.
Naturally, I would have used at instead of on.
What differences are between "at the end" and "on the end"?