Business card for a student? I know there are quite some questions about business cards, but as far as I can see they are all about professors, PhDs, and so forth. I have finished my Bachelor's degree in Germany and I am currently taking my Master's (computer science).

Although there is a certrain trend in Germany (especially in STEM-related fields, even more in Startup culture) towards a more casual way of dealing with each other, there are still some things that are considered rather negative. I guess compared to other countries we are still kind of strict in our behavior, even in defiance of globalization.

One such thing is business cards for students. Albeit scientific degrees enjoy a very good reputation in a CV in Germany, students are often seen like non-professionals. It would be an exaggeration to say "school-kids"...but sometimes even in this direction.

Hence, many (business) professionals would not recommend business cards for students. Some even consider students with business cards as self-exposers and would disrespect them.

However, I am mostly talking to people in Academia (or sometimes human resources people). Since I have written my first publications, people started asking for my contact information at conferences (and sometimes at exhibitions, like CeBIT for example). Even though many of them are German, there are also lots of international people.

In fact I will visit a big conference in my field in Japan this year.

So I am wondering what "etiquette" does exist in other countries for business cards (as a student)?
Is it probably helpful to have some that you can hand out at events? Or is it considered rather negative (at least in business quarters), like in Germany?
First of all you mentioned that you already finished your bachelors. In Germany this is normally considered a "berufsqualifizierender Abschluss" which means that with your B.Sc./B.Eng. (at least "on paper") you are considered a trained professional capable of doing a job related to your field of study. So nothing "pretentious" about that.

When I was in the same stage (B.Sc. finished, M.Sc. in progress, also in Germany) I also had no business card and in hindsight it was bad to not have any. I was very often asked for a card at conferences or after presenting our work to potential or current industry partners. One older guy at a conference in Germany even got a little "angry" at me when i couldn´t give him contact information in form of a card because he thought it was unprofessional for students not to have one.

As suggested in an other answer just keep it simple (just your name, kind of your bachelors, department and contact info). Maybe your university even has a template or guidelines for it.
And if you worry to be seen as pretentious, just don´t spread them like flyers but wait for people to ask for them.