I was wondering which trainers are the best ones for rematch purposes in PokéGear, as you can only add 8 numbers (Mom and Elm's number's can't be removed). Couldn't find a simple list that had all of the trainers that you can have a rematch against listed with their final teams, so I created one, the sources being my own game, Serebii and Bulbapedia. If there are any mistakes or something's missing, feel free to note so I can edit the list. All of the trainers are listed with their final teams:
Route 30: Youngster Joey - Raticate (Lv.21)
Route 31: Bug Catcher Wade - Butterfree (Lv.14), Butterfree (Lv.14), Beedrill (Lv.15), Butterfree (Lv.14)
Route 32: Picnicker Liz - Weepinbell (Lv.19), Nidorino (Lv.19), Nidoqueen (Lv.21)
Route 32: Fisher Ralph - Qwilfish (Lv.17), Goldeen (Lv.19)
Route 33: Hiker Anthony - Graveler (Lv.25), Graveler (Lv.27), Machoke (Lv.29)
Route 34: Picnicker Gina - Skiploom (Lv.26), Skiploom (Lv.26), Ivysaur (Lv.29)
Route 34: Camper Todd - Geodude (Lv.23), Geodude (Lv.23), Psyduck (Lv.26)
Route 35: Bug Catcher Arnie - Venomoth (Lv.28)
Route 35: Juggler Irwin - Voltorb (Lv.18), Voltorb (Lv.22), Voltorb (Lv.26), Electrode (Lv.30)
National Park: Pokéfan Beverly - Granbull (Lv.30)
National Park: Schoolboy Jack - Gloom (Lv.28), Electrode (Lv.31)
Route 36: Schoolboy Alan - Natu (Lv.20), Tangela (Lv.22), Quagsire (Lv.20), Yanma (Lv.25)
Route 38: Lass Dana - Psyduck (Lv.29), Ampharos (Lv.29)
Route 38: Schoolboy Chad - Mr. Mime (Lv.27), Magneton (Lv.31)
Route 39: Pokéfan Derek - Pikachu (Lv.36)
Lighthouse: Sailor Huey - Poliwhirl (Lv.34), Poliwrath (Lv.34)
Route 42: Fisher Chris - Goldeen (Lv.32), Goldeen (Lv.32), Qwilfish (Lv.34)
Route 43: Picnicker Tiffany - Clefairy (Lv.37)
Route 43: PokéManiac Brent - Nidoran-M (Lv.28), Nidoran-F (Lv.28), Nidorina (Lv.30), Nidoking (Lv.32)
Route 44: Bird Keeper Vance - Pidgeotto (Lv.35), Pidgeot (Lv.37)
Route 44: Fisher Wilton - Goldeen (Lv.31), Seaking (Lv.35), Seaking (Lv.35)
Route 45: Black Belt Kenji - Onix (Lv.30), Machamp (Lv.37), Onix (Lv.30), Hitmonlee (Lv.35)
Route 45: Hiker Parry - Onix (Lv.38)
Route 46: Picnicker Erin - Ponyta (Lv.36), Ponyta (Lv.36)
Route 26: Cooltrainer Gaven - Victreebel (Lv.38), Kingler (Lv.38), Flareon (Lv.38)
Route 26: Cooltrainer Beth - Rapidash (Lv.42)
Route 27: Bird Keeper Jose - Farfetch’d (Lv.41)
Route 27: Cooltrainer Reena - Starmie (Lv.37), Nidoqueen (Lv.39), Starmie (Lv.37)