I have a creative SB X-Fi Xtreme Audio, And i faced so many problems with this card regarding compatibility with Linux.
Now i am looking for a new audio card and want to make sure that this time it will be compatible with linux.
If you don't know a websites that has a list of supported Linux audio cards just tell me what audio card you are using on Linux.
Thanks for help!
Maybe the hardware compatibility list on linuxcompatible.org can help you.
Maybe this can help too: Sound Cards & Drivers - linux-sound.org
Here is another list: Sound cards - Linux Hardware Compatibility HOWTO
For Ubuntu specifically, see HardwareSupport/Components/SoundCards on the wiki.
You can find a list of certified audio cards in the component certification catalog.
You could also take a look here at the ALSA project wiki's list of supported sound cards. (Here's the site search).