From George Mason University, the Mason OER Metafinder (MOM) provides users with "real-time, simultaneous search across 23 different sources of open education materials." CLICK HERE to learn more about MOM. CLICK HERE for MOM's advanced search page.
From SUNY Geneseo's Milne Library, the Openly Available Sources Integrated Search (OASIS) "searches open content from 114 different sources and contains 440,269 records."