The mipmap bias of the Texture.
A positive bias makes a Texture appear extra blurry, while a negative bias sharpens the Texture.
Note that using large negative bias can reduce performance, so it's not recommended to use more than -0.5 negative bias. In most cases you can achieve better sharpening of the Texture by using anisotropic filtering.
Mipmap bias doesn't work with the following:
MaterialPropertyBlocks.
Some graphics APIs. For example Metal, or OpenGL ES unless you use custom shaders.
Additional resources: Texture.anisoLevel, Texture assets.