You can't have a soundtrack thread without the main theme of Sakura Wars.
Geki! Teikoku Kagekidan. My favorite version is Sakura Wars 2's opening movie.
And then we have the new iteration from Shin Sakura Wars.
So many fans (me included) fucking cried when we heard the new version during the reveal.
Edit: Also, giving a shoutout to Sakura Kakumei, the mobile spinoff of Sakura Wars. The soundtracks are composed by the composer of the original series, Tanaka Kouhei and his protégé, Higashiohji Kenta. Here's its main theme SAKURA HIKARU Revolution:
And a Jazz arrangement revealed as the main girl's birthday event. In the game, as her spiritual power was sealed by her mother, she literally can't sing (because according to SW lore, singing is linked to one's spirit) so she sings through her mind. The protagonist (ie. players) has the ability of seeing the future, which somehow allows them to hear her song. I honestly cried when reading the event. It is very wholesome.