Seva is sanskrit for selfless service; seva is performed without any expectation of result or reward. As wikipedia states, "such services can be performed to benefit other human beings or society." However, seva is not necessarily a thankless or unrewarding work; volunteering our time and skill to help others is deeply satisfying. 
In addition to seva and karma yoga, the yoga of action, or the path of seva, I have the great fortune and pleasure of often working in a professional capacity to bring yoga to populations that may never step foot inside a studio.   
Below please find links to some of the organizations that I work with in a volunteer and professional capacity. These organizations are working hard to provide trauma-sensitive yoga and mindfulness to populations often left out of yoga marketing. See if one is calling your name; maybe you can get involved by volunteering, donating, or becoming a recipient of the wonderful service these organizations provide! 
Susan's Place - Care for the Homeless fights homelessness by delivering high-quality and client-centered healthcare, human services and shelter to homeless individuals and families, and by advocating for policies to ameliorate, prevent and end homelessness.
Special Citizens Futures Unlimited  -

SCFU is committed to the development and delivery of a comprehensive, integrated system of services, which has as its primary

purpose the promotion and attainment of independence, inclusion, individuality, and productivity for adults and children with

Autism. Special Citizens has a workforce of over 200 employees supporting over 300 people with Autism Spectrum Disorders

throughout New York City, The Bronx, Queens and Westchester County.

Three and a Half Acres Yoga - THAY creates partnerships with community based organizations and local institutions—amplifying existing service-based offerings and integrating new methodologies into structures of authority, providing trauma-informed yoga throughout the Harlem community.
Connected Warriors - provides evidence based Trauma-Conscious yoga therapy programs for Servicemembers, Veterans and their Families while establishing a new and progressive safe haven community for all military members, their families and volunteers worldwide.