A good team leader would not need to ask you about the good things you've done in the past year. They should be attentive enough to your personal progress, and helping you shape your learning, that they might actually know about more things you did great this year than you.

If you are that team leader, and you need to ask, it may be good to take 30 minutes of personal time, and review within yourself, what you think that person has done good this year. If you can't, try the following approach:

Ask colleagues of that person about one good thing they have seen him do this year (or month). compile a list of five such things.

Now, compile a list of actions that you will take,   in the coming month, and year, to make sure this never happens again.