SDN and OpenFlow are among the hot topics both in academia and industry. There are a lot of commercial and open source developments around OpenFlow and SDN in general. In this chapter, we tried to provide an overview of important open source projects around SDN/OpenFlow. Beacon, Floodlight, Maestro, Trema, FlowER, and Ryu were additional SDN/OpenFlow controllers that we covered in this chapter. Besides, we also briefly mentioned other important active projects, such as FlowVisor, Avior, RouteFlow, OFLops and Cbench, OSCARS, Twister, FortNOX, Nettle, Frenetic, and OESS.