the_pink_terror | A list of nicknames.

Kenpachi Zaraki - Ken-chan/Kenny
Ikkaku Madarame - Cueball/Smoothie/Pachinko head/Pinball head
Yumichika Ayasegawa - Yun-Yun
Ichigo Kurosaki - Icchi
Sajin Komamura- Koma-Koma/Doggy
Makizō Aramaki - Maki-maki, Mini Mustache (when she forgets his first nickname) and Whisker (in between the first 2, only used shortly)
Maki Ichinose - Maki-chan
Nanao Ise - Nana
Shunsui Kyōraku - Shun-shun
Retsu Unohana - Re-chan
Izuru Kira - Izurun
Yoruichi Shihōin - Boobies
Genryūsai Shigekuni Yamamoto - Gramps
Mayuri Kurotsuchi - Mayurin
Byakuya Kuchiki - Byakushi/Byakkun
Orihime Inoue - Jiggles/Boobies
Ganju Shiba - Monkey
Yasutora Sado - Muscles
Uryū Ishida - Pencil
Jūshirō Ukitake - Ukki
Shūsuke Amagai - Ama-Ama

Non Canon - For Siren's Pull