Kinship ties/Family Networks– play very important role even in large cities, but they usually become less dependent on physical proximity and are formed more by voluntary choice.
Neighborhood/Community groups – connected with a specific area: local resident associations, watch and security groups, religious congregations.
Interest Groups – clubs for hobbyists, sport leagues, golf clubs, book reading clubs, etc. Cities contribute to the emergence of these groups due to population concentration that allows finding niche interests groups forming.
Occupational and professional groups – employees, working teams, coworkers.
Ethnic and Cultural groups – immigrants’ and diasporas’ communities creating mutual support groups.
Subcultures – music movements, art collectives, activist organizations, gaming teams, etc. Cities are influential in the development of subcultures.
Online-to-offline gatherings – Meetup-type communities and local Discord chat groups.

Georg Simmel believed that urban lifestyle makes people indifferent to the environment, meaning that more importance goes to the choice of voluntary groups in the city.
Louis Wirth argued in his “Urbanism as a Way of Life” that the number of social bonds in cities is numerous but not deep.
Robert Putnam, in his “Bowling Alone”, mentioned the decline of social clubs in modern urban life and the escalating debate whether the trend continues today by going online.
Granovetter’s idea of the “impact of weak ties” is also applicable.

Source(s), Link(s), Inspritation(s) and Further Reading:

Social Groups: The Concept

Classification of Social Groups