Anything by UVERworld or Aimer, really. I can't decide on an absolute favourite, but I really like:
- Kazeno Uta from Tales of Zestiria the X, for how inspiring and motivational and energy-filled it sounds. The animation is also pretty.
- Brave Shine from Fate/Stay Night: Unlimited Blade Works, again for the art and Aimer's strong vocals.
- katharsis from Tokyo Ghoul:re, because it, in my opinion, sounds better than unravel. It's stronger and more emotional to me.
- Colors of the Heart from Blood+, because of UVERworld (no surprises here) and its meaningful lyrics.
And if anime movie openings count as well, then:
THERE IS A REASON from No Game No Life ZERO, because of its strong and emotional lyrics, enough to make anyone cry
Colorful from Puella Magi Madoka Magica: Rebellion, because of ClariS's beautiful vocals and pick-me-up vibe.
Apologies for the tangent, I'm a very indecisive person. --'