There are a lot of kumite forms in Goju Ryu. The foundation is Kakie. It helps with reflexes, attacking, counter, balance and to get a feeling of how a opponent behaves when challenged. If you master Kakie you will have a real good foundation for all other forms of kumite. The next variation is probably Ippon kumite, or rather Kihon ippon kumite. One attack, one defence and one counter attack. After that we have San dan gi, three level techniques. Very fun and can be very free, But there are also Sanbon and Gohon kumite, three and steps sparring, kiso and bunkai kumite, ju/jiyu kumite and other variations. Not all forms of kumite are used in all styles, and some have even more variations.