Although I enjoy songs mainly because they sound good to me (usually because they are catchy / pop-rocky), there are some endings that stood out to me beyond just their audio:

Comedy a.k.a. Kigeki by Hoshino Gen (Spy x Family)

• The visuals is essentially Anya’s dream. I especially like the latter part, of them having happy, heart-warming family time.

Sweet Sign by Misaki Nako (100 Girlfriends)

• The visuals show a small, self-contained story, and showcased the essence of the girls’ relationship with each other.

Kimi wa Boku Niteiru by See-Saw (Gundam SEED Destiny)

• Whenever something sad happened in the show, this ending song starts playing, elevating the feeling of sadness.

unlasting by LiSA (SAO: Alicization - War of Underworld)

• Looks like major spoilers.

My Nonfiction by Kaguya-sama cast (Kaguya-sama season 3)

• It tends to get overshadowed by the Chika dance, but this ending does everything well: great audio, great visuals (with the change in art style), and most of all, it’s the perfect follow-up to the episode.