Here are a few networking resources.
Mathematical Association of America (MAA)
https://www.maa.org/ has Membership, About MAA, Meetings, MAA Publications, Competitions, News, Programs, and Communities.
http://www.maa.org/careers/profiles.html is for careers in mathematics and sciences.
National Association of Mathematicians (NAM)
https://www.nam-math.org/ is a non-profit professional organization in the mathematical sciences with membership open to all persons interested in the mission and purpose of NAM, which is to promoting excellence in the mathematical sciences and promoting the mathematical development of all underrepresented minorities.
The Benjamin Banneker Association (BBA)
http://bannekermath.org/ is a nonprofit professional organization with goals to advocate for the educational and professional needs for all children - mostly African American
National Institute of Science (NIS) BETA
https://nisweb.org/index.php/education/index is continually striving to increase the numbers of well-trained minority scientists by giving students the necessary academic support, research experience, internship opportunities, and career choices needed to become top working professionals.
Gulf States Math Alliances (GSMath)