Electric diode:

https://en.wikipedia.org/wiki/Diode

Optical diode:

https://en.wikipedia.org/wiki/Optical_isolator

Thermic diode:

https://en.wikipedia.org/wiki/Thermal_diode

Acoustic diode:

https://publishing.aip.org/publishing/journal-highlights/designing-acoustic-diode

Gravitational diode:

https://www.linkedin.com/pulse/gravitational-diode-could-lead-futuristic-star-trek-rayan-de-zeeuw/

Magnetic diode:

http://www.eenewspower.com/news/magnetic-diode-could-extend-battery-life-100-times

 

And?

1 hour ago, franco malgarini said:

Gravitational diode

This caught my interest, did you intend to start a discussion? The comments on the topic, in the link you posted as a reference, suggests that this is not considered mainstream science. 

9 minutes ago, Ghideon said:

This caught my interest, did you intend to start a discussion? The comments on the topic, in the link you posted as a reference, suggests that this is not considered mainstream science. 

I think the only one that is not mainstream (and is, in fact, complete fantasy) is the "gravity diode". The others are real things.

No idea what the point of the thread is, though.

 

1 minute ago, Strange said:

The others are real things.

Thanks! I was not sure about Magnetic diode, and I had no intention clicking the link.

7 minutes ago, Strange said:

No idea what the point of the thread is, though.

Agree, I was wondering why the list mixes mainstream science and fantasy devices. It is not a very helpful list, but I'm open for discussion if the OP returns to the topic.

34 minutes ago, Ghideon said:

I was not sure about Magnetic diode, and I had no intention clicking the link.

It is a fairly mainstream technology magazine (I think I may have met the author, years ago). 

3 minutes ago, Strange said:

It is a fairly mainstream technology magazine (I think I may have met the author, years ago). 

Thanks again, I've learned more than I initially hoped for when I commented in this topic!

 

Side note: Maybe the topic was intended for the puzzles section, as an "Spot the Odd One Out" quiz? You would have responded quicker than me...

Link removed