Baten Kaitos Origins' Le Ali Del Principio, a calm yet intense tune that plays near the end of the amazing journey that is Origins @Super_Boom . It also gives me extra feels that is kind of a family tune, Motoi Sakuraba composed the overall melody, lyrics written by his wife and their 9 year old daughter sang the lyrics.
And for a game that I like too much despite its flaws, Xenoblade Chronicles X, absolute killer OST, god bless Hiroyuki Sawano.
I can whole-heartedly agree with both of these, particularly the Baten Kaitos one. Holy Chitoge did that game have a fantastic OST, I can listen to it all day and never get bored. The story behind that particular song really stands out though.
Outside of that, most of what I would add here has already been mentioned. The Super Mario Odyssey song was sublime, and the song that played during the Xenoblade 2 credits had me actually bawling given what had happened moments before. Lost in Thoughts All Alone in FE: Fates was a really suburb song that tied the entire game(s) together with surprisingly deep lyrics, both in English and the original. And Twilight of the Gods in FE: Echoes is just...*forgets how to speak*
Since I should add something, I'll use this one. It probably doesn't count, but since 14 year old me liked to pretend that there was really lame choir making these synth noises that were supposed to sound like a choir, I'm gonna include it anyway.