Country close to Zurich for 2 days of exploring

www.sbb.ch/en to get all the train schedules for your travels, and if you look at the map you'll see Germany is not too far away from Zurich...as the crow flies.

I won't ask the question "are you sure you have seen everything in Switzerland?"
By "2 day trip" I am guessing you mean 1 night, so a train trip of 2-4 hours is acceptable.

1) Strasbourg, with an option of adding either Colmar and the Alsace wine Villages. The villages require a car, or detailed study of limited bus times.

2) Black Forest. Possibly via Freiburg im Breisgau.

3) Lindau and Bodensee (Lake Constance).
Konstanz itself you can do as a day trip from Zürich. If it is summer, you must visit Insel Mainau ( https://www.mainau.de/en/welcome.html ), a bus from Konstanz station gets you there.

4) Oberstdorf in the Bavarian Alps. A bit difficult to get to, but worth it.

5) Italian Lakes, for example Stresa on Lake Maggiore, or Menaggio on Lake Como (bus from Lugano)

6) Innsbruck. Possibly combined with Salzburg, but thta is a bit too far for just 2 days.

Thank you for your reply! I didn’t say I’ve seen everything in Switzerland... I have been going to Switzerland 2xs a year for several years and during this leg will be in Switzerland for about a month and thought it would be fun to do a short trip to a close country during winter😊
I do have some flexibility so 2 nights or even 3 nights could work!!!
Thank you so much for all of your information!!!!