Parque Anhanguera is one of São Paulo's largest municipal parks, covering a broad reforested area in the city's northwest. It is less polished than Ibirapuera and less dramatic than Cantareira, but it gives access to open green space, trails, and patches of recovering Atlantic Forest.
It is mainly worth considering if you are staying in or deliberately exploring the northwest of the city. For most short visits, São Paulo's more central parks and museums will be easier to fit in.