  Understanding disk evolution and dissipation is essential for studies of
planet formation. Transition disks, i.e., disks with large dust cavities and
gaps, are promising candidates of active evolution. About two dozen
SED-selected candidates have been confirmed to have dust cavities through
millimeter interferometric imaging, but this sample is biased towards the
brightest disks. The Spitzer surveys of nearby low-mass star forming regions
have resulted in more than 4000 Young Stellar Objects (YSOs). Using color
criteria we have selected a sample of ~150 candidates, and an additional 40
candidates and known transition disks from the literature. The Spitzer data
were complemented by new observations at longer wavelengths, including new JCMT
and APEX submillimeter photometry, and WISE and Herschel-PACS mid and
far-infrared photometry. Furthermore, optical spectroscopy was obtained and
stellar types were derived for 85% of the sample, including information from
the literature. The SEDs were fit to a grid of RADMC-3D disk models with a
limited number of parameters: disk mass, inner disk mass, scale height and
flaring, and disk cavity radius, where the latter is the main parameter of
interest. A large fraction of the targets possibly have dust cavities based on
the SED. The derived cavity sizes are consistent with imaging/modeling results
in the literature, where available. Trends are found with Ldisk/Lstar and
stellar mass and a possible connection with exoplanet orbital radii. A
comparison with a previous study where color observables are used (Cieza et al.
2010) reveals large overlap between their category of planet-forming disks and
our transition disks with cavities. A large number of the new transition disk
candidates are suitable for follow-up observations with ALMA.
