While it is difficult to definitively rank the top 10 pioneers in affordable housing, here is a list of individuals who have made significant contributions in this field:

1. Ellen Lurie Hoffman: Co-director of the National Housing Law Project, focused on affordable housing policy and advocacy.
2. Jack Markowski: Former CEO of Community Investment Corporation, known for providing affordable housing financial resources and emerging market expertise.
3. Angela Boyd: Senior Advisor at Local Initiatives Support Corporation (LISC), known for her work in developing affordable housing strategies and funding mechanisms.
4. Ron Terwilliger: Founder of Terwilliger Center for Innovation in Shelter and former CEO of Trammell Crow Residential Company, focused on affordable housing solutions and funding initiatives.
5. Eileen Fitzgerald: Former CEO of NeighborWorks America, dedicated to community development and affordable housing programs.
6. Mercy M. Jimenez: Director of the Housing Initiative at the Urban Strategies Council, focused on affordable housing advocacy and community development.
7. Matthew Desmond: Sociologist and author of “Evicted: Poverty and Profit in the American City,” shedding light on housing inequality and the impact of eviction on low-income communities.
8. Bob Simpson: Former President and CEO of Simpson Housing Solutions, dedicated to providing affordable housing options and promoting sustainable communities.
9. Ruth Ann Norton: CEO of Green and Healthy Homes Initiative, focused on creating healthy and affordable homes for low-income families.
10. Iola Williams: Housing Advocate and Executive Director of Bridge Meadows, known for developing intergenerational housing models that serve low-income families and elders.

This list represents only a few pioneers in the field, and many more individuals and organizations have contributed significantly to affordable housing initiatives.