Tomb Raider Definitive Edition: Whenever Lara picks up a torch, your controller turns into a real-life guiding light, flickering yellow and red to mimic the in-game flame. Atmospheric when you're playing in the dark, and useful for an impromptu round of campfire stories.
Destiny: Bungie's shooter offers a number of colors to indicate states, including the ever-popular red for low health, white to match Ghost's flashlight, and yellow if your super attack is fully charged. That last one's perfect for backseat players who love to tell people what they already know.
Alien Isolation: Creative Assembly puts the shock into DualShock with arguably the best light bar feature to date. The controller mirrors the in-game motion tracker, pulsing white light against green in time with the device to indicate someone is nearby, or... something. Throw in the creepy speaker noises and you've just added jeebies to go with those heebies.
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Grand Theft Auto 5: In addition to changing color based on which character you're playing, the light bar flashes red and blue whenever the cops are on your tail. You know, just in case there was any confusion.
Infamous Second Son: A real karma chameleon. The strength of the hue emitted indicates your karma level; a nice strong red and you're clearly a bit of a bastard. On the more gimmicky side, when you hold your DualShock vertically to spray paint, the light bar matches the color of the graffiti.
Transistor: The light bar pulses the same blue as the game's talking weapon, flashing in sync with the big sword's speech. The idea, presumably, is to make you feel like you're holding the Transistor, minus having to drag around something twice your size.
Honorable mentions:
Fez (color changes to match in-game time of day),
Peggle 2 (a rainbow fireworks show when you beat a level),
Thief (shines a bright white when you're out in the open),
Hohokum (matches the ever-changing color of the Long Mover),
Outlast (goes green when night vision is activated)
