Daichi and Sugawara would call their partner either daddy, mommy or honey. Though Sugawara would probably call his partner mommy, regardless of their gender.
Asahi and Yamaguchi would call their partner angel or snowflake. Yamaguchi would also shorten his partner’s name.
Nishinoya and Tanaka would call them empress/emperor, king/queen, or even god/goddess.
Ennoshita would call his partner princess/prince or sweetheart.
Hinata would call his partner sunshine or sweet pea.
Kageyama would call his partner his better half or darling.
Tsukishima and Kuroo would call their partner babe/boo/bae, or anything that struck their partner’s nerves like shortie or something.
Oikawa would call his partner honey or sweetie.
Bokuto would definitely call his partner gorgeous or beautiful.