Pokémon Ruby Version, Sapphire Version, and Emerald Version - Places
Slateport City
Here you can find the house of the Name Rator, who can help you change the nicknames of your Pokémon. Note that you can’t rename Pokémon you didn’t get yourself.
Verdanturf Town
Here you can find a lady on the southwest who can tell you how much the first Pokémon in your party likes you.
Mossdeep City
The boy at the southwestern house will tell you where you built a Secret Base.
You may notice that one of the doors in Mossdeep City "appears to be locked." This door is accessible by using battle e-Cards and an e-Reader while at the door.