Sentence examples for last but from inspiring English sources

"last but" is not a complete sentence and is not grammatically correct.
It can be used as a transition phrase in a sentence, but it needs to be followed by another phrase or clause to make sense. For example, "Last but not least, I want to thank all of you for your support." This phrase is often used to introduce the final item or point in a list or to emphasize the importance of the last point being made.