We work with a small number of non-profits startups in every YC batch, usually between 2 to 4 companies. We started working with non-profits in 2013 and have worked with more than 30 companies so far. Here is a list of the non-profits that have gone through the YC program so far.
While 501c3 non-profit companies vary greatly in strategy, we favor those companies that strive to cover their operating costs by charging fees for the products & services they create rather than relying on donations. We do this for two primary reasons: (1) Charging users for your product ensures that you provide the value you claim to deliver. Users of free products & services rarely complain. Paying users complain loudly; they will let you know when you’ve gone off course. (2) You are not as vulnerable to market downturns. Donations dry up quickly in economic downturns. Revenue-generating products and service can insulate you from that.
Non-profit startups that charge fees for their products and service are also more similar to for-profits startups. Consequently, a lot of the advice we give at YC and much of the curriculum during the batch is directly applicable to both. During the batch, non-profits are mixed in with the for-profit startups.