In (¬_¬) the eyes are the "not sign" from logic, where ¬A means "not A". Its short tail points down, so both eyes seem to glance to the side. The flat line for a mouth says the person is not amused.
The parts of (¬_¬)
¬U+00ACNot sign. An eye looking sideways.
_U+005FLow line. A flat mouth.
The monocle face ಠ_ರೃ
Both eyes are letters from the Kannada script, used to write the Kannada language in southern India. ಠ is the same letter that makes the famous look of disapproval ಠ_ಠ. The right eye is ರ, the letter "ra", with a vowel sign that hangs below it like the chain of a monocle.
The parts of ಠ_ರೃ
ಠU+0CA0Kannada letter TTHA. The left eye.
ರU+0CB0Kannada letter RA. The eye with the monocle.
ೃU+0CC3Kannada vowel sign vocalic R. The chain.
People send it with words like "indeed" or "how curious", in the voice of a fancy old gentleman.
Faces you can type on any keyboard
These use only keys on a normal keyboard, so they never turn into boxes. They are also safe for usernames and old apps.
A few more to type yourself: (._.), (o_O) and (-_-).