The nature of high-energy ($>$100 MeV) gamma-ray sources, lacking counterparts at other wavelengths, remains an enigma decades after they have been discovered. The Second Fermi Gamma-ray LAT (2FGL) Catalog released about 2000 sources in 2011. The majority of the identified Fermi sources includes extra-galactic AGNs and Galactic $gamma$-ray emitter pulsars. However, there are still 30% unidentified (unID) Fermi sources. We selected a few unID Fermi sources and search for their counterparts via multi-wavelength data in order to identify their source types via their Spectral Energy Distribution (SED). We aim to perform identification of these unID GeV $gamma$-ray sources, and then to discover new type of $gamma$-ray emitter.