https://steamdb.info/app/1460060/
https://store.steampowered.com/app/1460060/Traveler_of_Artcaster_Soundtrack
!addlicense ASF app/1460060
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https://steamdb.info/app/1327730/
https://store.steampowered.com/app/1327730/AkiRobots_Soundtrack
!addlicense ASF app/1327730
https://steamdb.info/app/1449740/
https://store.steampowered.com/app/1449740/PixARK_Soundtrack
!addlicense ASF app/1449740
https://steamdb.info/app/1455330/
https://store.steampowered.com/app/1455330/The_Wednesday_Soundtrack
!addlicense ASF app/1455330
https://steamdb.info/app/1455860/
https://store.steampowered.com/app/1455860/Tetra_Online_Original_Game_Soundtrack
!addlicense ASF app/1455860
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https://steamdb.info/app/1117610/
https://store.steampowered.com/app/1117610/7776_II___OST
!addlicense ASF app/1117610
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https://steamdb.info/app/1501860/
https://store.steampowered.com/app/1501860/Dread_X_Collection_Year_1_Soundtrack
!addlicense ASF app/1501860
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https://steamdb.info/app/1506670/
https://store.steampowered.com/app/1506670/Where_Is_My_Parking_Spot_Soundtrack
!addlicense ASF app/1506670
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https://store.steampowered.com/app/1478510/LOST_EPIC_MINI_SOUNDTRACK/
"A mini sound track from 『LOST EPIC』the newest game from Team EARTH WARS.
Out now for free for a limited time to celebrate the goal of the twitter follow campaign!
『Prism Flare』the OP song written by Yusuke Nakamura, sung by Jun Futamata and BGMs by yuma yamaguchi and kana yoshizawa with a total of 5 songs."
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https://steamdb.info/app/1469790/
https://store.steampowered.com/app/1469790/Niharielys_Spatial_Adventure_Original_Soundtrack
!addlicense ASF app/1469790
https://steamdb.info/app/1524480/
https://store.steampowered.com/app/1524480/The_Poop_On_2020_Podcast
!addlicense ASF app/1524480
https://steamdb.info/app/1377660/
https://store.steampowered.com/app/1377660/Project_Exhibited_Soundtrack
!addlicense ASF app/1377660
https://steamdb.info/app/1524420/
https://store.steampowered.com/app/1524420/Cyber_Manhunt__Original_Soundtrack
!addlicense ASF app/1524420
https://steamdb.info/app/1532220/
https://store.steampowered.com/app/1532220/Zniw_Adventure_Soundtrack
!addlicense ASF app/1532220
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https://steamdb.info/app/1507460/
https://store.steampowered.com/app/1507460/Nebula_Within_Soundtrack
!addlicense ASF app/1507460
https://steamdb.info/app/413720/
https://store.steampowered.com/app/413720/Grand_Class_Melee_2__Original_Soundtrack
!addlicense ASF app/413720
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https://steamdb.info/app/1472670/
https://store.steampowered.com/app/1472670/Slay_the_Dragon_Soundtrack
!addlicense ASF app/1472670
https://steamdb.info/app/1527850/
https://store.steampowered.com/app/1527850/Firework_Original_Soundtrack
!addlicense ASF app/1527850
https://steamdb.info/app/386860/
https://store.steampowered.com/app/386860/Viscera_Cleanup_Detail__Soundtrack
!addlicense ASF app/386860
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https://steamdb.info/app/1536810/
https://store.steampowered.com/app/1536810/_Soundtrack
!addlicense ASF app/1536810
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https://steamdb.info/app/1543230/
https://store.steampowered.com/app/1543230/Speed_Limit_Soundtrack
!addlicense ASF app/1543230
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https://steamdb.info/app/1529980/
https://store.steampowered.com/app/1529980/CHACAL_Soundtrack
!addlicense ASF app/1529980
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https://steamdb.info/app/1126650/
https://store.steampowered.com/app/1126650/The_Forgotten_Soundtrack
!addlicense ASF app/1126650
https://steamdb.info/app/1241190/
https://store.steampowered.com/app/1241190/Beat_Rush__Original_Game_Soundtrack
!addlicense ASF app/1241190
https://steamdb.info/app/1557970/
https://store.steampowered.com/app/1557970/EvoWave_Soundtrack
!addlicense ASF app/1557970
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https://steamdb.info/search/?a=app_keynames&type=15&keyname=243&operator=3&keyvalue=1
There's also some music which uses the "no cost" license instead:
https://www.steamgifts.com/discussion/XCks6/free-music-in-steam-can-add-without-base-game#7VTtgYy
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https://steamdb.info/app/1546020/
https://store.steampowered.com/app/1546020/Blue_Fire__Original_Soundtrack
!addlicense ASF app/1546020
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https://steamdb.info/app/1559030/
https://store.steampowered.com/app/1559030/Anoyo_zero_Soundtrack
!addlicense ASF app/1559030
https://steamdb.info/app/1556830/
https://store.steampowered.com/app/1556830/Children_of_Morta_Family_Fireside_Fables
!addlicense ASF app/1556830
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https://steamdb.info/app/1574430/
https://store.steampowered.com/app/1574430/Through_The_Fragmentation_OST
!addlicense ASF app/1574430
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https://steamdb.info/app/1573650/
https://store.steampowered.com/app/1573650/Ranch_Simulator_Music
!addlicense ASF app/1573650
https://steamdb.info/app/1566320/
https://store.steampowered.com/app/1566320/Captain_Coffer_2D_Soundtrack
!addlicense ASF app/1566320
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https://steamdb.info/app/1549790/
https://store.steampowered.com/app/1549790/Retis_Tormentum_Soundtrack
!addlicense ASF app/1549790
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https://steamdb.info/app/1557570/
https://store.steampowered.com/app/1557570/_
!addlicense ASF app/1557570
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239 Comments - Last post 7 minutes ago by y2
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You can add these soundtracks (DLC) in your library, even if you not have a base game or she sold for the money in store.
Some DLC sold in the store for real money, for example soundtrack for Frostpunk, but you can add him in library - free!
Little Inferno Soundtrack - https://steamdb.info/app/1270140/ (Base game not free)
7 Billion Humans Soundtrack - https://steamdb.info/app/1270120/ (Base game not free)
Human Resource Machine Soundtrack - https://steamdb.info/app/1273200/ (Base game not free)
Master of Orion: Soundtrack & Score - https://steamdb.info/app/468020/ (Base game not free) [DLC hide in the store]
Scythe: Digital Edition - Soundtrack - https://steamdb.info/app/893130/ (Base game not free)
Cymatically Muffed - Soundtrack - https://steamdb.info/app/1105750/ (Base game not free)
Sector Six OST - https://steamdb.info/app/469520/ (Base game not free)
Odyssey Soundtrack - https://steamdb.info/app/992770/ (Base game not free)
The Search Soundtrack - https://steamdb.info/app/720110/ (Base game not free) [Can receive game free april 13-14]
Nyanco Dream Soundtrack - https://steamdb.info/app/1257730/ (Base game not free)
OSK - Soundtrack - https://steamdb.info/app/1210950/ (Base game not free)
Frostpunk Original Soundtrack - https://steamdb.info/app/966350/ (Base game not free, DLC too not free in Steam store)
Nyanco Channel Soundtrack - https://steamdb.info/app/1251180/ (Base game not free)
Colum and His Friends: Soundtrack - https://steamdb.info/app/1225450/ (Base game still not released)
Frontier Pilot Simulator Soundtrack - https://steamdb.info/app/1253560/ (Base game not free)
The Executioner Soundtrack - https://steamdb.info/app/1249650/ (Base game not free)
Dying Light Original Soundtrack - https://steamdb.info/app/798540/ (Base game not free)
Walden, a game - Soundtrack - https://steamdb.info/app/1044710/ (Base game not free)
The Void Rains Upon Her Heart - Soundtrack - https://steamdb.info/app/810530/ (Base game not free, DLC too not free in Steam store)
Super Arcade Racing Soundtrack - https://steamdb.info/app/1192110/ (Base game not free)
Sable's Grimoire Soundtrack - https://steamdb.info/app/941900/ (Base game not free)
Candice: Da Instrumentalz - https://steamdb.info/app/887430/ (Base game not free)
Tomboys Need Love Too! Soundtrack - https://steamdb.info/app/942100/ (Base game not free)
Tallowmere – Soundtrack - https://steamdb.info/app/1225360/ (Base game not free)
Areia: Pathway to Dawn - Soundtrack - https://steamdb.info/app/1227670/ (Base game not free)
An Octave Higher - Basic Soundtrack - https://steamdb.info/app/415430/ (Base game not free)
Unhack - Original Soundtrack - https://steamdb.info/app/343720/ (Base game not free)
Squids Odyssey Soundtrack - https://steamdb.info/app/927660/ (Base game not free)
Monster RPG 3 Soundtrack - https://steamdb.info/app/885040/info/ (Base game not free)
TAL: Arctic 3 - Soundtrack - https://steamdb.info/app/932840/ (Base game not free)
Other:
Galactic Rangers VR - Digital Artbook - https://steamdb.info/app/1246300/ (Base game not free)
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