You may not find any
here, as this is a small OpenBSD community. You will be much better off asking for quagga users on the ports@ mailing list.
Note that the OpenBGP project is a component of the OpenBSD Project, and users of quagga and zebra who use BGP or OSPF have been migrating to it.
Website:
http://www.openbgpd.org/
Disclaimer: I don't use any of this stuff, as I don't run either protocol.