Well in addition to food stamps, opebo, we have unemployment insurance and medicaid that come to mind. Utility companies give a break on utility bills to low income folks. There is also Section 8 housing, which subsidizes housing costs. One can make the case that this is all inadequate perhaps, but one cannot make the case that there is no safety net at all.
Before the ACA's medicaid expansion (which is now optional), childless adults were not covered under Medicaid unless the state opted to cover them (which few did):
http://www.kaiserhealthnews.org/stories/2010/march/08/childless-adults-health-reform.aspxhttp://www.washingtonpost.com/blogs/wonkblog/wp/2012/07/05/what-happens-if-a-state-opts-out-of-medicaid-in-one-chart/
