If you have cloud saves enabled, you will still see those even if you have deleted the local ones.
You can also delete your local savegames by deleting the respective folder. By defaut they're stored here: Documents\Anno 1800\accounts\
This thread was added on February 04, 2020, with posts from Ubi-Thorlof.
Original Post
Is there a way to delete old games? I have games I have completed and no longer need.