This list of Free/Royalty Free samples was compiled from a few sources and reposted in few other places for people looking for resources for their projects/music/etc. so might as well post it here too, heh. Feel free to add to the list, though naturally it should be free/royalty free.

The #GAMEAUDIOGDC Bundle (Part 2, 16GB+)

The #GAMEAUDIOGDC Bundle (Part 3, 20GB+)

The #GAMEAUDIOGDC Bundle (Part 4, 30GB+)

52,261 free music samples

8458 free sound samples

3.5 gigs of Orchestral SF2's

A bunch of quality SF2's

GM Soundfont made specifically for vgm

2 gigs of sfx sample pack from boyss

2000+ samples from audio micro (requires email registration)

Genuine Sound Ware sound fonts

NTONYX sound fonts

free SFX from Psionic Games

The Open Bundle (alternates on Soundcloud, OpenGameArt)

SoundBible

Incompetech

DL-Sounds

DrPetter's sfxr and bfxr

99Sounds

pdsounds

Music by Marcelo Fernandez

Music by Eric Matyas

Sound Effects by Jesús Lastra

LabChirp

Music by James Opie

Adobe Audition DLC (10k+ sfx, music)

The Game Creators Pack by Jonathan So

Music Pack's by Bocuma

OpenGameArt

Music by Punch Deck

http://99sounds.org/ has been a great resource for me.

I have some free music on my site: http://www.marcelofernandezmusic.com/royalty-free-music/

Check my porfile https://jalastram.itch.io

Sysop-Delco, thank you very much for featuring my asset pack on here!

Very nice! 

I posted some free music and SFX a couple days ago too! Here you go: https://rhetoricsff.itch.io/debutante-musicsfx-pack-i

I have a whole lot of various sounds on my freesound.org page: https://freesound.org/people/DWOBoyle/

Hello guys, also check out PlayOnLoop, there are hundreds of 8-bit and 16-bit chiptunes on the Retro Game music category. Each track on catalog comes with a free downloadable edit. Cheers :-)

I was on trying to find a site something almostly like this descriptions, which can give me the wave or mp3 sounds in my game. Specially, I need few sci-fi sound bundles. If there would be any site, where I can search the sounds or noises, that I'll need!

I have a free coin & money sound library up on itch.io for anyone who'd find that sort of thing useful :)
https://shapeforms.itch.io/the-mint-coins-and-money-lite

Here's my contribution: https://freesound.org/people/jasonlee3071/

I don't know if this post is still active but here's mine https://railroadstudio.itch.io/royalty-free-music-for-video-games-and-animation

Thnaks for list! 

https://www.free-stock-music.com/

This is a big royalty free / creative commons music (CC-BY) library categorized by genre and mood. You can use CC-BY music in your games as long as:
1. Put the music title and artist in your game credits.
2. The author doesn't have additional conditions for using his music in games and apps. Check authors website for that.

I'm finally giving away the drum samples I made from my nintendo ds. I think the raw recordings are in there too. And the second link is a bunch of drum loops from the DS Drums series I produced. I'm using gumroad to host but it's all free. Let me know if you use any of it!

https://bluechameleon.gumroad.com/l/dsdrums 

https://bluechameleon.gumroad.com/l/dsdrumloops

Also adding mine here:

Gnarly metal scrapes, impacts, and friction rich in ultrasonic content that's great for sound design

https://itch.io/embed/2561808

Ultra hi-rez EMF interference recordings that make excellent source material for SciFi sound design

https://itch.io/embed/2099196

Quirky, organic percussion one-shots

https://itch.io/embed/1846700

22 multi-sampled patches created on the analogue Teenage Engineering POM-400 synth

https://itch.io/embed/1844442

Free complete TR-707 drum kit

https://itch.io/embed/1845232

Around ~250.000 game sounds free to use in all non-commercial projects: https://www.weloveindies.com/en :)

Thank for sharing

You can refer to the free source: https://soundboard39.com/

these links from OP are all dead

http://open.commonly.cc/

http://soundbible.com/

http://ntonyx.com/sf_f.htm

http://www.psionicgames.com/resources.html