I want to talk about the Pokeymans music. Just cool moments in the soundtracks of these games.
One that I don't hear a lot about is the themes that change between Pokémon Black and White and their sequels. The game already has a great sense of the passage of time, between NPC dialogue and the events and general, but my absolute favorite of them has to be the changes to N's theme. Throughout the first games, his theme doesn't quite sit right. It feels incomplete and out of place, ending on an odd loop. But in the sequels, when you meet him again in the postgame, his theme is completed. The new section becomes the loop, as if to show he's changed as a person, that he's moved on from his past. He's complete as a person and is no longer held back by Team Plasma's motives.
I don't know if anyone else has weird nerd shit analyses like this, but I like these games' soundtracks enough I just wanted to talk about it.
I'll accept the spinoff games too! They've got cool music as well.

Good thread because I've been listening to Gen IV music a lot while doing work.

Pokemon DPPT has alternate versions of overworld music based on in-game time, so there's day/night versions of almost every track when you're exploring. I wasn't all that much of a fan of the night time versions of each track but funnily enough, the night version of the Pokemon League is one of my absolute favorite tracks in the entire series. Such a beautifully haunting electric piano piece... I can't even begin to describe what kind of mood it sets being one of the last pieces you hear at the end of your journey, like the calm before the storm.

https://www.youtube.com/watch?v=Re0eZgv-kno

There are two tracks that came to mind reading this post:

Dreamyard on Pokemon Black & White, is the one track that I recall most impacting me in the main series as a grown up; it feels very different to the established general uplifting or thrilling ambient tracks: In the context of the game, it is a particularly emotional part, you finding the villain team grunts before beginning to kicking a Munna in front of you, to obtain Dream Mist from it, arguing they are fighting for the freedom of Pokemon: The mist in context can project a person's dream; the grunts says they are going to use it to make people want to release their Pokemon, by showing them dreams to manipulate their hearts. After you battle them, you are left with this music:
https://www.youtube.com/watch?v=tQAeGGGMhA0

I stopped playing, to assimilate the scene and music; it made me feel a special connection to Pokemon, I had forgotten had in the past had: Dreaming of having beautiful friendship with Pokemon as a kid after seeing the anime, and too on my first times playing Pokemon RSE; the playful melodies of the music reminds me of the cute and heartwarming fantasies I had with Pokemon, and the constant dominant dissonance culminating in ethereal moods hooking me with hopefulness for a happy resolution that seems barely out of reach; the track, much like a dream feels has a certain awareness to my grown melancholy about these dear fantasies about friendship, and entices me to keep hopeful in a never concluding progression that keeps out of a reachable resolution.

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Rustboro City from Pokemon RSE is a track that I think didn't fully appreciated the first time listening at it; but after a long time off from the series, listening at a Famitracker cover of

by BotBr Blaze Weednix, of its track once more:
https://www.youtube.com/watch?v=Y3auFhxfsmI

Strongly brings back a warm feeling in my chest, exploring the city and walking in nearby tall grass, entering shops, feeling my chest lighter: Memories of a bright time, that seemed unlocked by; reminiscing me of a past time, I used to fantasy about having adventures with Pokemon I found in the game! Memories of Pokemon RSE being more than a game to me, but being part of my life outside of playing the game; fantasying about and playing as a child adventures related to my progress in the game, having different fantasies with Pokemon at different times of the day, a really rich experience, in a world of Pokemon, where Pokemon friends are in!

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While writing this, recalled Pokemon RSE Route 113: It talks to me in a special way, and did in a moment I felt understood by nobody, reaching in, ash begins to fall, and this begins to play:
https://www.youtube.com/watch?v=wfARFF9S5Jg

Since a kid this scene and track made me fantasy about wolves/Mightyenas singing/hownling together the melody of this track in a snow landscape, while snowing; this community of wolves in my fantasy made me feel understood: It was a kind of interaction/communication I felt needed; a deep emotional connection and intimate moment, I felt understood and heartfully welcome to sing out my heart and grieves out. Uuuh uuuh uuuh~ uuuu uuuh-uuuh uuuh-uuuh, uuuh-uuh uuh-uuuh~ uuh-uuuh~ uuh-uuh-uuuuuh!~

Whilst X and Y may not be the best games in the series. I will never forget entering lumiose city for the first time and the music that accompanied it.
Whenever I play the stage in Smash Bros Ultimate I still get chills down my spine from the song.

Some other stuff I'd like to gush over:
In Sun and Moon, the remix and retooling of the final battle theme from Red and Blue into something more acoustic for the Battle Tree is just so good. I can't get over how good this theme is. Particularly the part with the fret slide at around 1:00 always made me get hype.
https://www.youtube.com/watch?v=F-FaNn0939w
On the topic of Sun and Moon (probably one of the best modern Pokémon soundtracks) I also miss the day/night themes from this game. Konikoni City's is a fun one, going from a traditional Asian sound to 80s synth:
https://www.youtube.com/watch?v=lzEvew0NIOM

theres straight up quotes from shnabubula and cryptovolans in the pokemon legends arceus battle theme, lol. which isnt a coincidence since the composer knows a lot of the digifu/chiptune musicians