An Angklung, a Kolitang, and a gamelan.
Singapore's history, being rather short, did not have time to develop its own traditional dance. As of current, most Singaporeans consider a dance to be Singaporean when it includes dance elements of the 3 major races (Chinese, Indian and Malay) and others (the smaller minority groups such as Caucasians). Being a multiracial country, Singapore places emphasis on the peaceful and harmonious coexistence of its people, and when translating that into dance or any aesthetic form, incorporation of elements from the various races are very common and widely accepted as 'Uniquely Singapore'. I believe this is the start of the development of Singapore's own unique dance (and hopefully, culture as well).