We investigate gluon transverse momentum dependent (TMD) correlators defined as Fourier transforms of nonlocal matrix elements. These correlators include process-dependent gauge links that bridge the nonlocality. The dipole-type correlator has one future- and one past-pointing gauge link and can, in the limit of small x, be related to a correlator of a single Wilson loop. We discuss the parametrization of Wilson loop correlators for unpolarized, vector polarized, and tensor polarized targets. We investigate the relation between the functions in the Wilson loop correlators and the usual gluon TMDs in the limit of small x. This analysis may shed light on which gluon TMDs are leading or suppressed in the small-x limit. We also study the positivity bounds on the gluon TMDs.