JSF is a specification included in the Java EE platform. There are different implementations of JSF from different vendors. I know Oracle provides Mojarra & Apache provides MyFaces. Are there any other implementations of JSF from other vendors?
The reference implementation Mojarra and the independent Apache implementation MyFaces are the only real and practically available JSF implementations.
Legend has it that IBM at one time did had their own implementation as well, but obviously they don't use this any more (AFAIK WAS 7 was shipped with both Mojarra and MyFaces, leaving the choice to the user).
There supposedly is (was) a mythical Chinese/ Eastern JSF implementation available. A bunch of Java EE specs have been implemented by (for us) obscure Eastern companies that market their closed source products solely for their internal market. Even in the era of the Internet it's hard to validate whether these products actually exist and/or if they aren't just repackaged and rebranded versions of the well known implementations.