Leitmotif/Video Games/Visual Novel

General example. Virtually every Dating Sim game has leitmotifs for each character.
All of Clannad's main female characters had their own themes. The ending song of the anime, Dango Daikazoku, even goes on to have the same tune as Nagisa's eponymous theme music.
- Worth noting that virtually all of the main female characters in Key Visual Arts' visual novels feature their own themes, and there's even one for a male character. (Natsume Kyousuke from Little Busters)
- Non-animate things have leitmotifs, too. For an example, a song called Snowfield plays when it's snowing.
- On the same topic, a few themes are used for any event filling a certain theme, such as Shining in the sky and The Place Where Wishes Come True being used for many of the Crowning Moment of Awesome instances, A couple of idiots and Meaningful ways to pass the time for many of the comedic plot development scenes, Sping Wind and To the same heights for plot development in general and Distant Years along with Town, Flow of Time, People for flashbacks
Umineko no Naku Koro Ni has a few of these, most of which are brain-meltingly awesome. Most notably, Battler has "Dread of the Grave", Beato has "Organ Opusculum in C Minor", Lambdadelta has "Miragecoordinator", and Eva-Beatrice has the Soundtrack Dissonance-tastic "Happiness of Marionette".
- As said in the anime section, Higurashi no Naku Koro Ni has a few too.
- According to fans, Kinzo's theme is la divina tragedia. OH DESIRE!!!
Fate Stay Night has several, including Die Lorelei for Ilya (which is also a pre-existing song), The Golden King for Gilgamesh, and All Evils of the World for the Shadow.
- You also have Emiya for Shirou and Archer, and for Saber you have Kodoku na Junrei for the Heartwarming and Tear Jerker scenes, and The Sword Of Promised Victory whenever she decides to unveil her Noble Phantasm and do something Badass, and for villains, you have Kotomine's Church On The Hill. And if you want, you can look into Fate Zero for The Berserker and The Lancer.
The Tokimeki Memorial series makes extensive use of this trope : each character in the series has its own iconic tune, which plays each time they show up, and even starts to play a fraction of seconds before the character appears on screen (so the first cue of who shows up is actually musical). Played with in Tokimeki Memorial 2 with Kaori Yae, who has a more cheerful variation of her Leitmoif, which plays when she finally overcomes her painful past and turns back to her former Genki Girl self, and fully falls in love with the protagonist who patiently and affectionately helped her along the way.
- Mitsumete Knight, Tokimeki Memorial 's Spiritual Successor, made the same use of this trope. And also played with the trope with Raizze Haimer, who has two variations of her Leitmotif, the somber "Cold Lips" : the first, "Salishuan the Spy", an epic, battle-engaging tune which plays when Raizze reveals to you her identity as Salishuan the Spy of the Eight Generals of Valpha-Valaharian, and challenges you to a duel in order to avenge her father, the leader of the Eight General Wolfgario the Ravager, slayed by you in a duel a week earlier ; the second, which follows just after the first variation if she's deeply in love with you, named "Sorrowful Blade", is a heartwrenching tune playing as Raizze is conflicted between her love for her father and thus her duty to avenge him, and the love she feels for you. And you'll need to hear this second variation if you don't want her to meet a sad fate.
Characters in the Girls Love VN Akai Ito and Aoi Shiro have Leitmotif, but Yumei's Itsuka no Hikari was actually promoted to a vocal single later (along with Nushi's sinister Wheel of Fortune).
Each of the heroines in Maji De Watashi Ni Koi Shinasai gets their own, of course, and Yamato has one himself as well. Various remixes of the two ending songs and the insert song are also used sparsely, and to good effect.