For each UGS, we report all the $\gamma$-ray blazar candidates with their IR colors (i.e., $c_{12}$ = \[3.4\]-\[4.6\] $\mu$m, $c_{23}$ = \[4.6\]-\[12\] $\mu$m and $c_{34}$ = \[12\]-\[22\] $\mu$m, together with their errors, $\sigma_{12}$, $\sigma_{23}$, $\sigma_{34}$, respectively), the distances in arc seconds between the $\gamma$-ray position and the selected [[*WISE*]{}]{} source, the $s_b$ and $s_q$ values, the class and the association confidence $\pi$ that there is a [[*WISE*]{}]{} source of the same class within the ROC (see Section \[sec:association\]).

In addition, we found that there are 157 unidentified $\gamma$-ray sources that do not have clear $\gamma$-ray blazar counterpart within their SRs and are classified as outliers of the [[*WGS*]{}]{}. The lack of association for these sources could be due to a lower accuracy of the $\gamma$-ray position that might occur close to the Galactic plane or to the systematic uncertainties of the diffuse emission model used in the 2FGL analysis. The whole UGS sample will be reconsidered for associations with $\gamma$-ray blazar candidates when the all-sky [[*WISE*]{}]{} survey will be available.

Assuming that all the 2FB blazar associations are correct, on the basis of our test (see Section \[sec:test\]), we can argue that within our sample we would expect about 41 