I know a lot of people commented on a thread asking for help to find certain players that either lost communication with them or decided to switch servers depending on the situation a lot of it was repeated more than once and I decided to give up, below I have posted 2 links that will help you find out what server they were last on please do note it may not be accurate so check the Minecraft name checker and it will tell you if the player has changed their name and then search it on Minecraft statistics. Good Luck and I hope it becomes helpful to some!

FYI: make sure to use the search bar across from minecraft statistics and not the one below to get better results!

https://minecraft-statistic.net/en/players/

https://namemc.com/