These emojis use that cute wavy w character (ω) to make the mouth look happy.

Squiggly W Mouth
(^・ω・^ )(=^-ω-^=)(=^・ω・^)y=
( ノ^ω^)ノ゚(_´ω`)(。・ω・。)
(︶ω︶)(`・ω・´)”(´ω`★)
(^ω^)(◐ω◑ )∩( ・ω・)∩
ヾ(。・ω・。)୧( ॑ധ ॑)୨d(=^・ω・^=)b
o(U・ω・)⊃V(=^・ω・^=)v川´・ω・`川
(´꒳`)(^ω^)(❁´ω`❁)
(´-ω-`)ଘ(੭ˊ꒳ˋ)੭✧(´へωへ`*)
( ^ω^)( ^ω^)(✌’ω’)✌
✌(‘ω’)✌✌(‘ω’✌)٩(ↁωↁ❀)
˚✧₊⁎( ˘ω˘ )⁎⁺˳✧༚(◜௰◝)✾(〜 ☌ω☌)〜✾
(´∩ω∩`)