Color centers in diamond can be devised in quantum applications. The most successful exemplary color center is the nitrogen-vacancy (NV) center in diamond that has high spin ground state with favorable spin coherence time from cryogenic to room temperature that can be read out either optically or electrically. However, the optical properties of NV center are not ideal for certain quantum applications. Therefore, a search for alternative color centers with improved optical properties has been started in diamond. This paper briefly reviews recent experimental and theoretical results on the color centers alternative to NV center in diamond which are promising solid-state defect quantum bits for quantum communication and other applications.