Throwing Your Shield Always Works

When Captain America throws his mighty shield
All those who chose to oppose his shield must yield!

—Captain America theme song, The Marvel Superheroes

A Sub-Trope of Throwing Your Sword Always Works and Improbable Use of a Weapon, a shield is thrown at a target. Varies from just hitting to slicing.

Anime and Manga

In Gundam Wing, The Shenlong Gundam throws its shield at few enemies in space, whilst the Deathscythe's (rocket-powered, Laser Blade-tipped) shield is actually its primary ranged weapon.
Athrun kills Tolle in Gundam Seed by throwing his mech's enormous shield through his aircraft's cockpit, decapitating him in the process. Ouch.
- Then Shinn one-ups him by throwing his shield at the Freedom and firing at the shield. Since the shield has anti-beam coating, the shot ricochets off the shield and hits the Freedom. Needless to say, Kira really didn't expect that.
In Saint Seiya, the "weighing pans" of the Gold Cloth of Libra become huge dual shields when assembled as armor. The chains from which they hang in its "balanced scales" form spool into the shields themselves. When using one as a weapon, the wielder holds onto the chain and flings the shield at its target, edge-first, and then he reels it back with the chain (taking care not to be plowed over by it on its return trip.) Aside from their unsurpassed defensive power, the Shields (like all Libra weapons) are impossibly destructive regardless of the user's personal strength, capable of shattering the legendary Pillars that hold up the Seven Seas... but not the Main Breadwinner, the principal support at the center of Poseidon's Shrine.

Comic Books

Captain America, the patron saint of this trope, does this with the addition of his shield being a Precision-Guided Boomerang (and what little we see of his older classic-shape shield proves it was just as effective a projectile).

Film

In the The Lord of the Rings film, Aragorn is at one point pinned to a tree by an Orc shield that just barely misses decapitating him.
- In the second movie, Legolas sends a similar shield flying through the air and impaling an Orc after surfing down a flight of stairs.

Literature

Used by Derfel in The Warlord Chronicles during a pre-battle single combat. He spots that the Saxon champion he's about to fight is going to charge and overwhelm him with speed and brute force, and counters by throwing his shield into the other man's face and then gutting him while he's knocking it aside.

Live-Action TV

Kamen Rider Decade: it's Apollo Geist's favorite move. Unfortunately, throwing his shield never works, but he keeps doing it.
- It works, though not as originally intended, exactly once: In the final episode of Kamen Rider Decade, Apollo Geist throws his shield at Decade, but Kuuga Takes The Bullet for him and gets killed in the process. Then It Got Worse...

Toys

Bionicle: A normal Skrall throws its Saw Blade Shield at Gresh during an Arena Match.
- Inverted in the Mata Nui Online Game, where a Disk, a projectile weapon, is used to shield the holder against Rahi attacks.

Video Games

The Buckler shield in Tribes: Vengeance can be thrown (and guided with the mouse) at enemies. It's very useful for killing enemies in midair.
The Ragnarok Online ability Shield Boomerang
Protection-specced Paladins in World of Warcraft can do this with their Avenger's Shield talent, in a clear Shout-Out to Captain America (comics), leading member of the Avengers. Warriors prefer the use of the other trope instead.
The Ghosts N Goblins video game had a shield... it was intended to be a short-range throwing weapon.
In the computer game Lands of Lore: The Throne of Chaos, chucking shields at a certain boss kills it faster than either throwing actual weapons or using the weapon you're supposed to kill it with.
The Boomerang Shield from Mega Man Zero 1-3.
- Sigma in Mega Man X3 throws his shield like a boomerang once his health gets low enough.
Some of Goofy's attacks in the Kingdom Hearts series have him throwing his shield.
Both Sophitia and Cassandra of Soul Calibur have throws that involve shoving their opponent away and hurling their shield at them.
Kanji Tatsumi's Critical Hit animation in Persona 4 starts with him tossing his weapon (usually a shield of some sort) edge-first at the enemy, kicking it while it's stunned and then decking it with a right cross.
In Dissidia Final Fantasy, the Warrior of Light starts off half of his combos by throwing his shield at the enemy, pulling them in with it, and then following up with magic or a sword slash sequence.
- And, in Duodecim, he gets a HP attack that uses only his shield.
Possible in ADOM and Dwarf Fortress alike. Both games allow throwing of nearly any item, with shields not being excluded. ADOM even has a single Shield skill, which matters and is trained by both blocking attacks with a shield and throwing one from the missile slot. Due to shields' high mass, severally times higher than an arrow's, and lack of reusability, it generally isn't worth the weight.
Some of the Finis enemies in Devil May Cry 2 fight with razor-lined shields that they throw at you.
In Dynasty Warriors: Gundam, Johnny Ridden's Gelgoog can throw its shield as a boomerang.
Rygar‍'‍s Diskarmor, a shield with a chain attached to it to use as a yo-yo attack, is the video game grandpappy of this trope.
The Gladiatorial SRPG Gladius features this with the shield focused Myrmidon class as one of its more powerful set of skills.
In the Battle Clash/Metal Combat duology, Carlos is able to do this with both his mechs, the ST Baron and later the ST Viscount.
Several members of the Alexandria family of Soul Calibur throw their shields in a number of their attacks.
Shield Knight from Shovel Knight dual-wields small and large shields. She uses the giant shield to block frontal attacks, charge towards an opponent, and throw her shield which comes back like a boomerang. She can also bash her shield hard enough against a wall to cause the ceiling to collapse.

Web Animation

Haloid: during the battle between the Covenant and MC/Samus Aran, MC throws a Covenant shield at a Covenant Elite and cuts its off.
In Dead Fantasy II, Rinoa throws her shield/boomerang/buzzsaw Silenced Tear at an opponent.
Pyrrha Nikkos from RWBY, whose Greek Diphylon-like shield Akoúo̱ is designed to be thrown like a chakram. For extra effectiveness, she can control the shield with her Semblance of Polarity.

Web Comics

Goblins: Ha ha, looks like your useless, crappy shield isn't good for anything! Konk.

Western Animation

In The Herculoids, Zandor often used his shield as a weapon.
Samurai Jack: a Spartan throws his shield to slice a robot.
In the The Three Musketeers (part of The Banana Splits show) episode "The Haunted Castle", d'Artagnan throws a shield at a mook.
The title character of Steven Universe has a shield as his gem weapon inherited from his mother. While it's durable enough to take a charged shot from a Gem Warship, he can also throw it as a weapon that can cut through solid rock and damage metal.
The Turtle Miraculous, from Miraculous Ladybug, gives a person a turtle-themed costume with an unbreakable shield as the wielder's primary weapon. In addition to being used for for defense, it can be swung as a blunt weapon, and thrown at targets.