How to make transparent textures?

[Enceos]

I have added a decal plane to one of the objects of my model and I'm trying to display a texture on this plane without transparent background. Currently Unity fills all the transparency of my texture with grey background. In the texture import options I checked the "Alpha is transparency" option, but it doesn't work. "Alpha from grayscale" gives the same result even if I deliberately fill the texture background with gray color. How do I make the texture background disappear in Unity?

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Ok, found, there's a KSP Alpha, Translucent shader.

Unfortunately there is no Translucent Emissive