Many people ask the question, what are the best chords for R&B? Or what are R&B sounding chords, however there is never any simply direct answer to that however there are many ways to get an R&B or Neo Soul grooving or feeling.
The first thing is know your extended chords e.g. 7ths 9ths and 11ths as these are used a lot.
Know your diminished and altered chords e.g. dim, aug, sus
Understand how inversions work, as you will want to limit your finger movement with complex chords to avoid gaps in your playing.
For Neo Soul and R&B I suggest you use chords from at least 2 keys. The simple 2-5-1 will not sound soulful enough. For example, I recommend using a combination of the key of F major and Bb because the chords in this scale are similar but not the same. That slight difference in the keys gives that tension and r&b feel. E.g. Play Bb min 9th then play a Fmin9th. Different keys but do have some relationship between them.
Learn slash chords i.e. chords with the base key in a different location to the original key (similar to inversions) however having the bass key in a different place makes a very big different to the sound. Try the base key in a 7th or 9th position.
Listen to more Neo Soul and Jazz. This is important to get a feel of what you would like to play.