I guess Terry Tao would be a good example of collaborative mathematics? He was mentioned in another thread and I noticed the following while reading his wiki page:

> Within the field of mathematics, Tao is known for his collaboration with Ben J. Green of Oxford University; together they proved the Green–Tao theorem. Known for his collaborative mindset, by 2006, Tao had worked with over 30 others in his discoveries,[15] reaching 68 co-authors by October 2015.