Skip this step if you already have developer console enabled and know how to access it.

Whilst in-game, navigate to Options. Then, with Keyboard selected, click on Advanced. From here, tick Enable developer console and press OK. That's it!

You can now access the console by pressing either ` or ~ (located under Esc key) on your keyboard.

With the console open, enter one of the following commands from the list below to play your music of choice at any time:

(Please note that entering one of these commands whilst the automatic, randomised startup music is still playing will cause them to overlap. To fix this, see Step 3. Otherwise, you can enter multiple commands one after the other at any time, as the previous command will stop playing once a new one is entered).

play ui/gamestartup1.mp3 - Main Theme
play ui/gamestartup2.mp3 - Playing With Danger
play ui/gamestartup3.mp3 - Rocket Jump Waltz
play ui/gamestartup4.mp3 - The Art of War
play ui/gamestartup5.mp3 - Faster Than a Speeding Bullet
play ui/gamestartup6.mp3 - Petite Chou-Fleur
play ui/gamestartup7.mp3 - Right Behind You
play ui/gamestartup8.mp3 - Intruder Alert
play ui/gamestartup9.mp3 - Drunken Pipe Bomb
play ui/gamestartup10.mp3 - More Gun
play ui/gamestartup11.mp3 - A Little Heart to Heart
play ui/gamestartup12.mp3 - MEDIC!
play ui/gamestartup13.mp3 - Archimedes
play ui/gamestartup14.mp3 - Dreams of Cruelty
play ui/gamestartup15.mp3 - The Calm
play ui/gamestartup16.mp3 - ROBOTS!
play ui/gamestartup17.mp3 - Dapper Cadaver
play ui/gamestartup18.mp3 - Rise of the Living Bread
play ui/gamestartup19.mp3 - Red Bread
play ui/gamestartup20.mp3 - Three days to live
play ui/gamestartup21.mp3 - Seduce Me!
play ui/gamestartup22.mp3 - Stink Lines
play ui/gamestartup23.mp3 - It Hates Me So Much
play ui/gamestartup24.mp3 - Soldier of Dance
play ui/gamestartup25.mp3 - RED Triumphs!
play ui/gamestartup26.mp3 - BLU Triumphs!
play ui/gamestartup27.mp3 - Yeti Park
play ui/gamestartup28.mp3 - Saxton's Dilemma
play ui/gamestartup29.mp3 - Mercenary Park

play ui/holiday/gamestartup_halloween.mp3 - Haunted Fortress 2
play ui/holiday/gamestartup_halloween1.mp3 - Misfortune Teller
play ui/holiday/gamestartup_saxxy.mp3 - TF2 Saxxy 2011 Theme
play ui/holiday/gamestartup_soldier.mp3 - Saluting the Fallen

play ui/cyoa_musicdrunkenpipebomb.mp3 - Drunken Pipe Bomb
play ui/cyoa_musicfasterthanaspeedingbullet.mp3 - Faster Than a Speeding Bullet
play ui/cyoa_musicintruderalert.mp3 - Intruder Alert
play ui/cyoa_musicmedic.mp3 - MEDIC!
play ui/cyoa_musicmoregun.mp3 - More Gun
play ui/cyoa_musicmoregun2.mp3 - More Gun 2
play ui/cyoa_musicplayingwithdanger.mp3 - Playing With Danger
play ui/cyoa_musicrightbehindyou.mp3 - Right Behind You
play ui/cyoa_musicteamfortress2.mp3 - Main Theme

play music/bump_in_the_night.wav - Bumper Cars
play music/carousel_of_curses.wav - Carousel of Curses

play items/tf_music_upgrade_machine.wav - Upgrade Station
play music/mvm_start_wave.wav
play music/mvm_start_mid_wave.wav
play music/mvm_start_last_wave.wav
play music/mvm_end_wave.wav
play music/mvm_end_mid_wave.wav
play music/mvm_end_last_wave.wav
play music/mvm_start_tank_wave.wav
play music/mvm_end_tank_wave.wav
play music/mvm_lost_wave.wav

play ambient/medieval_dooropen.wav - Day of Defeat (British Victory Theme)

play music/bonus_round_30.wav

play music/conga_sketch_167bpm_01-04.wav - Conga (Loops)
play music/cossack_sandvich.wav - Kazotsky Kick (Loops)
play music/mannrobics.wav - Mannrobics (Loops)
play music/fortress_reel.wav - Square Dance
play music/fortress_reel_loop.wav - Square Dance Idle (Loops)
play music/taunt_bongos.wav - Runner's Rhythm
play music/trombonetauntv2.mp3 - The Fubar Fanfare
play player/brutal_legend_taunt.wav - The Shred Alert
play player/taunt_surgeons_squeezebox_music.wav - Surgeon's Squeezebox (Loops)
play player/taunt_didgeridoo_start.wav - Didgeridrongo (Loops)
play player/taunt_bumpkins_banjo_music.wav - The Dueling Banjo (Loops)
play player/taunt_bumpkins_banjo_music_fast.wav - The Dueling Banjo (Fast - Loops)
play player/taunt_disco.wav - Disco Fever
play player/taunt_eng_strum.wav - Frontier Justice Guitar Strum
play player/taunt_medic_heroic.wav - The Meet the Medic
play player/taunt_scorchers_solo1.wav - Scorcher's Solo
play player/taunt_scorchers_solo2.wav
play player/taunt_v01.wav - Amputator Medicating Melody
play player/taunt_v02.wav
play player/taunt_v03.wav
play player/taunt_v04.wav
play player/taunt_v05.wav
play player/taunt_v06.wav
play player/taunt_v07.wav
play player/ubertaunt_v01.wav - Uber Taunt
play player/ubertaunt_v02.wav
play player/ubertaunt_v03.wav
play player/ubertaunt_v04.wav
play player/ubertaunt_v05.wav
play player/ubertaunt_v06.wav
play player/ubertaunt_v07.wav
play items/taunts/badpipes/badpipes1.mp3 - Badpipes
play items/taunts/badpipes/badpipes2.mp3
play items/taunts/badpipes/badpipes3.mp3
play items/taunts/badpipes/badpipes4.mp3
play items/taunts/badpipes/badpipes5.mp3
play items/taunts/killer_solo/killer_solo_01.mp3 - Killer Solo
play items/taunts/killer_solo/killer_solo_02.mp3
play items/taunts/killer_solo/killer_solo_03.mp3
play items/taunts/killer_solo/killer_solo_04.mp3
play items/taunts/killer_solo/killer_solo_05.mp3
play items/taunts/scout_boston_breakdance/scout_boston_breakdance_02.mp3 - Boston Breakdance
play items/taunts/scout_boston_breakdance/scout_boston_breakdance_03.mp3
play items/taunts/scout_boston_breakdance/scout_boston_breakdance_04.mp3
play items/taunts/scout_boston_breakdance/scout_boston_breakdance_05.mp3

play misc/training_vid_arena_intro.mp3
play misc/training_vid_cp_badlands.mp3
play misc/training_vid_cp_dustbowl.mp3
play misc/training_vid_cp_granary.mp3
play misc/training_vid_cp_gravelpit.mp3
play misc/training_vid_cp_steel.mp3
play misc/training_vid_cp_well.mp3
play misc/training_vid_ctf_2fort.mp3
play misc/training_vid_ctf_well.mp3
play misc/training_vid_pl_badwater.mp3
play misc/training_vid_pl_goldrush.mp3
play misc/training_vid_tc_hydro.mp3

play ui/cyoa_musicdrunkenpipebomb_tv.mp3 - Drunken Pipe Bomb
play ui/cyoa_musicfasterthanaspeedingbullet_tv.mp3 - Faster Than a Speeding Bullet
play ui/cyoa_musicintruderalert_tv.mp3 - Intruder Alert
play ui/cyoa_musicmedic_tv.mp3 - MEDIC!
play ui/cyoa_musicmoregun_tv.mp3 - More Gun
play ui/cyoa_musicmoregun2_tv.mp3 - More Gun 2
play ui/cyoa_musicplayingwithdanger_tv.mp3 - Playing With Danger
play ui/cyoa_musicrightbehindyou_tv.mp3 - Right Behind You
play ui/cyoa_musicteamfortress2_tv.mp3 - Main Theme
play ui/tv_tune.wav
play ui/tv_tune2.wav
play ui/tv_tune3.wav

play music/class_menu_bg.wav (Loops)
play music/class_menu_01.wav
play music/class_menu_02.wav
play music/class_menu_03.wav
play music/class_menu_04.wav
play music/class_menu_05.wav
play music/class_menu_06.wav
play music/class_menu_07.wav
play music/class_menu_08.wav
play music/class_menu_09.wav
play music/mvm_class_menu_bg.wav (Loops)
play music/mvm_class_menu_01.wav
play music/mvm_class_menu_02.wav
play music/mvm_class_menu_03.wav
play music/mvm_class_menu_04.wav
play music/mvm_class_menu_05.wav
play music/mvm_class_menu_06.wav
play music/mvm_class_menu_07.wav
play music/mvm_class_menu_08.wav
play music/mvm_class_menu_09.wav

play ui/duel_challenge.wav
play ui/duel_challenge_accepted.wav
play ui/duel_challenge_rejected.wav
play ui/duel_challenge_with_restriction.wav
play ui/duel_challenge_accepted_with_restriction.wav
play ui/duel_challenge_rejected_with_restriction.wav
play ui/duel_event.wav
play ui/duel_score_behind.wav
play ui/vote_started.wav
play ui/vote_success.wav
play ui/vote_failure.wav
play misc/tf_domination.wav
play misc/tf_nemesis.wav
play misc/tf_revenge.wav
play misc/your_team_lost.wav
play misc/your_team_stalemate.wav
play misc/your_team_suddendeath.wav
play misc/your_team_won.wav
play misc/sniper_railgun_double_kill.wav
play ui/halloween_boss_chosen_it.wav
play ui/halloween_boss_defeated.wav
play ui/halloween_boss_escape.wav
play ui/halloween_boss_escape_sixty.wav
play ui/halloween_boss_escape_ten.wav
play ui/halloween_boss_player_becomes_it.wav
play ui/halloween_boss_summoned.wav
play ui/halloween_boss_tagged_other_it.wav
play ui/halloween_loot_found.wav
play ui/halloween_loot_spawn.wav

With the console open, enter the following command to instantly stop music:

snd_restart

Otherwise, music will stop prematurely when entering or leaving a game.

Thanks for reading! I hope you found this guide helpful. :D

Please bear in mind that this is by no means an exhaustive list. There are numerous other sounds that can be played that have not been listed here, including voice lines. You can play any sound if you can find the file's name/location by using GCFScape (e.g., play mvm/mvm_warning.wav, play ambient/lair/jungle_insect_loop2.wav and play vo/heavy_sandwichtaunt06.mp3). If there are enough requests, I will make another guide explaining GCFScape and how to find TF2 sound files.
Similarly, if I have made any mistakes or missed any music files, please point them out! I'll be quick to fix.

Also, please note that there is unfortunately no way to have music play in a continual playlist. You may want to counteract this by making keybinds (e.g., bind [key] play ui/gamestartup23.mp3).
There is also no way to loop music that does not loop by default.
These commands work with modded music.

Bye!