A random-looking eye animation driven by shading expressions (No 3D animation in it, only shader).
In the material instance, every aspect could be controlled to have different results, here below some examples:
Basic triangular curve
max(min((arccos(cos(time*pi))/pi), MinValue), MaxValue)
Same expression with some changes in length
The same expression is subtracted by another similar but with a different frequency
Now the expression is subtracted again with a curve with a very low frequency to have a look-like random movement.
The same just with clamped values
Same expression in the material editor (Some changes in values)