I live in Germany.
If you are traveling to Germany and unfortunately have lost or left something in a train or a bus, don't rush to contact the lost property center of the German transportation system, MVV. It's possible that you will come it out.
The following link is a lost properties search site provided by the German transportation.
The following is the search results on the website. As you can see, there are nearly 16 items just picked up by mobile phones. As of January 7, 2020, I wrote this post, it can be seen that it is frequently registered in the database.
The lost property center is close to Munich Station, so you may want to ask directly. Address: Elsenheimerstrae 61, 1. Stock 80687 Munich. As soon as you enter the building, you can see an elevator in front of you, so let's get on it.
I've been here to look for something I've left behind (unfortunately I wasn't able to find it), but if you ask a staff to show you something you dropped in English, they will show you the shelf where they've kept the lost stuff.
Finally, I put the link of the official homepage of the lost property center below. Please note,
That's all. Don't drop anything!