Nothing groundbreaking. But during my few years in game dev I built a relaxing game that had a spiritual component to it. Was one of my first games so.. plenty of flaws from a game design perspective. But one day I got an email from a player thanking me because the game helped immensely during a difficult time. Made my day... actually, I still think about once in a while. So, I guess you can say it was impactful for one ;)