  We present a sample of 19,583 ultracool dwarf candidates brighter than z
$\leq 23$ selected from the Dark Energy Survey DR2 coadd data matched to VHS
DR6, VIKING DR5 and AllWISE covering $\sim$ 4,800 $deg^2$. The ultracool
candidates were first pre-selected based on their (i-z), (z-Y), and (Y-J)
colours. They were further classified using a method that compares their
optical, near-infrared and mid-infrared colours against templates of M, L and T
dwarfs. 14,099 objects are presented as new L and T candidates and the
remaining objects are from the literature, including 5,342 candidates from our
previous work. Using this new and deeper sample of ultracool dwarf candidates
we also present: 20 new candidate members to nearby young moving groups (YMG)
and associations, variable candidate sources and four new wide binary systems
composed of two ultracool dwarfs. Finally, we also show the spectra of twelve
new ultracool dwarfs discovered by our group and presented here for the first
time. These spectroscopically confirmed objects are a sanity check of our
selection of ultracool dwarfs and photometric classification method.
