Are you looking for sounds to use to produce R&B music? Basically, there is no actual “R&B” sound. It is all about how you play or arrange regular instruments. However, there are certain instruments that tend to be used to R&B such as the Rhodes, and certain other EP patches.
Learning the theory for R&B is also important. It is a good idea to go through some Jazz & Blues theory and this is utilized a lot in R&B. I suggest you start the basics of building chord e.g. the 2-5-1 progression. In the key of C major this would be Dmin, G7, Cmaj. This progression will not sound very soulful however, it is a start for learning how to compose chords.
If you are having trouble creating chord progressions yourself, I do have a lot of pre-made R&B Chord progressions here which can be downloaded for free and used in your compositions.
With Premium membership, you can get access to the WAV and MIDI sounds too.