Hi! This chapter is by me, and is based on the games Alpha Sapphire and Omega Ruby. There are spoilers about post-game, but they are not very big spoilers. Enjoy!
.
.
.
In Omega Ruby and Alpha Sapphire (I have Omega Ruby :) ), I have found several small gym leader 'events'. There is one of these mini-events for six of the leaders, so I assume that there are one per leader. Here they are, in no specific order:
Roxanne
If you go to the Fossil Maniac's house at the very left side of Lavaridge Town, and head all the way back and through the door to where the Maniac really is, you will find Roxanne talking to him. She is begging for a fossil from the Fossil Maniac who turns her down, saying that his fossils are precious to him. Roxanne runs to the corner to cry a bit, but gets over it and apologizes for acting like a brat and walks away without talking to you.
Liza and Tate
If you go to the Mossdeep Department Store to the Secret Base decorations level, the two twins will be escorted in by some guards. These guards talk to you if approached and tell you that they are needed for some duty but are not doing what they want the twins to do, so the guards are buying the twins some presents to bribe/blackmail them with.
Wattson
After the game, go to the Square Tower, which is lighted up. Wattson will be there, staring at it. Talk to him and this leads to a rather large side-game. Wattson tells you that there is something wrong in New Mauville, which is why the tower is lighted up, and asks you to check it out. He allows you entry to New Mauville, which is right off the route below Mauville, so you can see the issue. There's nothing wrong there, but you can get a bunch of items and battle new Pokémon in this abandoned city. When you go back to Mauville to report your findings, you will be allowed to go to the second floor, which has all the apartments on it. Wattson lives here, and you need to find his room and talk to him and tell him nothing is wrong. You can explore the other rooms and find more items here. I think you can find the TM for Dream Eater on one of the residents' balcony. Wattson also gives you the TM for Thunderbolt and you find out he's married to an... Ace Trainer! Somehow, that couple doesn't work out in my brain :P
Wallace
I'm not sure about Wallace, but his event might be when him and Steven Stone meet up in Steven's room in a cutscene. Steven implies he will leave to travel again soon, and Wallace warns him to finish his Pokémon League duties. Wallace also says that he will help Steven with his Champion duties if and when Steven leaves. I personally feel that this is a huge hint that there might be a remake of Pokémon Emerald.
Norman
Norman has a bunch of lines post-game so any one of them can be one of these mini-events. For example, he says how proud he is that you as the character has become the Champion. He also gives you those Star Show tickets and is at home for a while.
Flannery
You can find Flannery in the Scorched Slab, where you find Heatran. She says she is looking for strong fire-type Pokémon, but she gets scared away or goes for more Pokéballs or something — I sort of forgot :P
Anyways, these are the mini-events I found. Tell me if you've found any of these, or if you have found something like these 'events' with Brawly and Winona. Those two were the only gym leaders I couldn't find. There may also be Elite 4 events too, so tell me if you have found those! Please review!