Gym leaders
Milo:
The logo of Turffield Orchards can be seen on the uniforms of Milo and Turffield Stadium Gym Trainers.
Milo's uniform number is "831", which can be read in Japanese as goroawase for 野菜 yasai, meaning "vegetables".
Nessa:
Nessa's uniform number is "049", which can be read in Japanese as goroawase for 泳ぐ oyogu, meaning "to swim".
Kabu:
Kabu's uniform number is "187", which can be read in Japanese as goroawase for 火花 hibana, meaning "sparks".
Allister:
Allister's uniform number is "291", which can be read in Japanese as goroawase for 憎い nikui, meaning "hateful".
Opal:
Opal's uniform number is "910", which can be read in Japanese as goroawase for キュート kyūto, meaning "cute".
Bede:
Bede's uniform number is "908", which can be read in Japanese as goroawase for クレバー kurebā, meaning "clever".
Gordie:
Gordie's uniform number is "188", which can be read in Japanese as goroawase for 岩場 iwaba, meaning "rocky area".
Melony:
Melony's uniform number is "361", which can be read in Japanese as goroawase for 寒い samui, meaning "cold".
Piers:
Piers's uniform number is "061", which can be read in Japanese as goroawase for 悪い warui, meaning "bad".
Marnie:
Marnie's uniform number is "960", which can be read in Japanese as goroawase for 苦労 kurō, meaning "hardship", or 黒 kuro, meaning "black".
Raihan:
Raihan's uniform number is "241", which can be read in Japanese as goroawase for 強い tsuyoi, meaning "powerful".
Bea:
Bea's uniform number is "193", which can be read in Japanese as goroawase for 戦 ikusa, meaning "fight"
Rivals
Avery:
Avery's uniform number is "026", which can be read in Japanese as goroawase for おつむ otsumu, meaning "brain".
Hop:
Hop's uniform number is "189", which can be read in Japanese as goroawase for 飛躍 hiyaku, meaning "leaping".
Klara:
Klara's uniform number is "881", which can be read in Japanese as goroawase for やばい yabai, meaning "dangerous".
Source: Trivia section of these characters in Bulbapedia
Hope this helps!
