The most famous are Su Qin and Zhang Yi. Su Qin is the main representative of Zonghe School, and Zhang Yi is the main representative of Lian Heng School. They all learn from guiguzi.
If you want to know their examples, please see here Baidu Encyclopedia Lian Heng:/view/view/17797.htm.
The most famous negotiators in modern foreign countries, some people call Kissinger the modern Su Qin and Zhang Yi.
Henry Alfred Kissinger, a famous contemporary American diplomat and expert on international issues, 1973 Nobel Peace Prize winner. He served as assistant and secretary of state for national security affairs in Nixon administration and secretary of state in Ford administration. His most famous example is to promote the establishment of diplomatic relations between China and the United States.
You can refer to Kissinger's entry and the entry of establishing diplomatic relations between China and the United States.
Of course, the most powerful negotiator in modern China is Premier Zhou Enlai. He talked about China's negotiations with other countries, and basically all diplomatic relations with foreign countries were negotiated by him after the founding of the People's Republic of China. There are too many examples to talk about.