Of course many / most of the starters could also be used at the end of the lesson!
Perhaps sum up the key notation and vocabulary from the lesson, see also the Vocabulary page for ideas.
Staying with questions and marking, trying an exam question and then checking / discussing the mark scheme can be a very appropriate lesson ending. Or you might want to have a slightly longer ending, with the all important idea of making things stick and give them a mini-test. Reading Make it Stick (The Science of Successful Learning) which discusses the use of testing as a learning tool convinces me even more that mini-tests are a good idea! During a revision week, all three of my Year 10 (UK age 14-14) lessons started with a mini test which seemed to work very well and I was very pleased when two students who had to be somewhere else in the first part of one of the lessons asked it I would send them the mini test for that day! Students need to recall information and the evidence suggests that testing is a better way of doing this than simply rereading material, a method often favoured by students. I am planning more plenary mini-tests, with the students I’ll definitely use the name I know they like, ‘Self-checks’ which I hope helps them realise they are as the authors suggest a learning tool, not something to be stressed by.
Aristotle apparently wrote “exercise in repeatedly recalling a thing strengthen the memory.”
Set a question and then use WolframAlpha to answer a query on a topic being studied. This is a chance to show students how they can check their work; you may want them to check homework for example. Or you might want to remind them how easy it is to use the Desmos Graphing calculator or perhaps some of the other calculators here.
For a novel plenary – plan ahead with a student – let them know they will be giving a vote of thanks for the lesson! This can include what has been learned and refer to any members of the class, perhaps comment on someone who asked a great question for example. This can work really well and the lesson may well end with everybody clapping!
It may be that you decide to use the end of the lesson to discuss what is coming next lesson and perhaps leave them a problem or task which you can tell them you wish to start work on as soon as they come into the next lesson.
…and speaking of the beginning of the next lesson….
as a slideshow: