One of the Scout's taunt attacks, called the Home Run, is a reference to Babe Ruth's famous "Called Shot" where he points to the sky, and hits a home run. The scout repeats this, and proceeds to bat any enemy caught in the swing 25 meters away as stated in the related achievement "Out of the Park".

The Stickybomb Launcher bears resemblance to a weapon cut from Half-Life 2, simply named the "Sticky Launcher". Had it been included, it would have functioned in an almost identical manner, except that it would stick to enemies as well as map surfaces. Also, the Stickbomb Launcher was originally supposed to be the Pipebomb Launcher seen in Team Fortress Classic, but it was changed to the Stickybomb Launcher as the Pipebomb Launcher's only difference was that you could detonate the pipebombs with the alt fire key. The model remains in the game.

When the 'Meet the Spy' video was released, The Sniper playermodel was updated in the game, adding the scar that the sniper got in the video. Previously, he had no scar on his face. It was never taken off the player model, and still has the scar.

The sniper rifle "The Classic" is a remake of the sniper rifle found in Team Fortress Classic.

There are unused particle effects with names that relate to the "Conga" taunt. This suggests that the taunt was originally intended to constantly spawn confetti, streamers and fireworks, which are either green or pink.

There are several unused voicelines that were added during the Love & War update that suggest a feature where the classes make fun of another player's weapon or hat, as well as a number of lines related to trading.

The community-created cosmetic item, the Toowoomba Tunic, is a reference to the tunic that Link from The Legend of Zelda wears.

In 2013, Valve and the tabletop game company WizKids collaborated to produce an exclusive chess set themed around Team Fortress 2 that was sold on Valve's website and on ThinkGeek. Each copy of the set came with a digital code for a hat called the Grandmaster, where the head piece would change as your killstreak increases. Aside from "Grandmaster" being one of the highest titles awarded to chess players by the International Chess Federation, the hat's item description references a pair of highly publicized chess matches in 1996 and 1997 between former World Chess Champion Garry Kasparov, and IBM's chess-playing computer Deep Blue.

Underneath the BLU spawn on the Banana Bay map is a summoning circle made up of toxic waste, candles, and a large collection of bananas. The circle was created to summon Poopy Joe, the first American Monkeynaut in the game's storyline, who died in his rocket moments after launch due to its Australium fuel supply (a mysterious metallic element first introduced in the 2010 Team Fortress 2 comic "Loose Canon") having been maliciously switched with gravel water by Mann Co., who was supplied America's entire stock of Australium fuel by the United States government in the first place.

Underneath the RED spawn on the Banana Bay are two conveyor belts that appear to be used for converting dozens of bananas into Australium bars.

In March of 2018, a passive effect called "Sketchek’s Bequest" was added to the Pyro's weapon the Axtinguisher which granted the player a speed boost after killing a burning opponent. This was named in honor of the YouTuber known as Sketchek, a prominent Pyro player in the community, who in 2015 claimed in a video to have a "terminal illness" that was getting worse and had later presumably died. However in 2019, Sketchek returned and stated that he lied about dying because he wanted to retire from the game as it had "ruined his life" and he wanted to "go out with a bang." The effect was subsequently removed in an update.

The Scout exclusive taunt, The Carlton, is based of the character Carlton Banks from the TV show The Fresh Prince of Bel-Air, in which the character preformed the exact dance named after himself.

During the 2012 Pyromania update, animations of all nine classes burning alive were added to the game and never used. It is unknown why this was done.

There was a free "Tux" item that was only available in the Linux version of Team Fortress 2. However, it's possible to get the Tux item using a Windows version of Team Fortress 2 by changing the name of the operating system to any Linux distribution, such as Ubuntu, Debian, SteamOS, etc.

There are 5 unused death sounds in the games files for the scrapped Civilian class.

Three of the Heavy's cosmetic items: "Carl", "Aqua Flops" and "Hunger Force" are all references to Carl Brutananadilewski from the Adult Swim TV show Aqua Teen Hunger Force.

Several taunts present in the 2014 Love and War Update were already in the game files back in the 2013 Halloween Update, but were quickly removed in the following update.

The Gun Mettle update included a new taunt called the Kazotsky Kick, which lets the player perform a Ukrainian 'Hopak' dance. While the taunt is active a song will play, which was first heard in the Counter Strike: Global Offensive map "de_train". However, the version that accompanies the taunt features more instruments, has vocal chanting, and is about 1.2 times faster.

The Soldier is voiced by Rick May, the same actor who voiced Peppy in Star Fox 64.

There are two unused models of the duck journal in the game.

The first is a yellow duck which isn't used in any of the styles.

Interestingly the second skin isn't implemented in the model, but the texture remains for it. It's set up to be paintable, and includes the phrase "Lets Eat!!!", a reference to the character Chica from Five Nights at Freddy's.

The Atomizer's original design was a simple re-skin of the Sandman bat, originally conceived with the name "The Atomic Punch". The name was likely changed to avoid confusion with Bonk! Atomic Punch.