In no particular order

I love anime, and this is all personal preference of course, so take everything I say with a grain of salt. Also this is for my school music class, so its not analyzing what most people look for.

1) Yumetourou — Kimi No Na Wa

The reason I love this song is because it starts off very soft and calming, then grows to become faster and louder, all while increasing the pitch. Also the instrumentals go from classical and soft, to rock and roll, and finally to a pop like song, and handles all the transitions gracefully.

2) Nandemonaiya — Kimi No Na Wa

Same like above, it starts off with a calming solo, transitioning into guitar instrumental. Then it handles the transition to slowly becoming louder and adds instrumentals slowly, which before you know it, changes it from a calming song, into a song that energizes you.

3) Again — Fullmetal Alchemist

Just like the other 2 it starts off very calm, and continues to rock. The reason I love this song so much is that it manages the tempo and beat all throughout the song even with all the changes in instrumentals, until one moment where it suddenly changes into another beat that's very catchy.

4) Fantastic Dreamer — Konosuba

This song unlike the other few, is very lighthearted and cheerful all throughout the song. It instrumentals like guitars, piano, and the sax to keep it exciting too, without it getting too boring with the same tune.

5) Gurenge — Demon Slayer

This song starts off calm, but almost immediately drops towards a more pop like instrumentals, which contrast to the classical voice. The speed also and tempo increases throughout the song giving it a feel of going through a story and something happening.

6) Fairy Tail Main Theme — Fairy Tail

The main theme has a great guitar solo, which then proceeds to become a full range of instrumentals, where the violin is the main instrument. This is one of my favorite songs because I love the violin and the guitar, and this includes both of them in a pop like song.

7) Nezuko's Theme — Demon Slayer

The song turns into an array of arpeggios after a while, which sounds amazing. This is because they mesh together to provide one great masterpiece. It goes from very solemn with very simple notes, to becoming like a choir, playing complicated series of notes on both the top and bottom register.

8) Resister — SAO Alicization

The song has a very catchy instrumental, where then it continues to go all over the place with the notes and has a rock feel to it, while with the voice, still feels vaguely classical.

9) Grand Escape — Weathering With You

Grand escape is an amazing song. I love it because of how soothing it is, and how calming and unobtrusive the instrumentals are, and they really flesh out the voice. The song also makes many dynamic changes, from soft music and calm, to louder/more complex music, while still being calming.

10) This Game — No Game no Life

I like this certain piece because it has many arpeggios and it has a lot of dynamic changes throughout the piece. The song goes through many different changes in tempo, which brings you to many different genre's from classical to rock.

EDIT: I'm usually not one to just edit and change my favorite songs, but this song is amazing, as well as the actual anime/webtoon.

11) Tower of God OP