We present a search for outer solar system objects in the 6yr of data from the Dark Energy Survey (DES). The DES covered a contiguous 5000deg^2^ of the southern sky with ~80000 3deg^2^ exposures in the grizY filters between 2013 and 2019. This search yielded 812 trans-Neptunian objects (TNOs), one Centaur and one Oort cloud comet, 458 reported here for the first time. We present methodology that builds upon our previous search on the first 4yr of data. All images were reprocessed with an optimized detection pipeline that leads to an average completeness gain of 0.47mag per exposure, as well as improved transient catalog production and algorithms for linkage of detections into orbits. All objects were verified by visual inspection and by the "sub-threshold significance", the signal-to-noise ratio in the stack of images in which its presence is indicated by the orbit, but no detection was reported. This yields a pure catalog complete to r~23.8mag and distances 29<d<2500au. The TNOs have minimum (median) of 7 (12) nights' detections and arcs of 1.1 (4.2) yr, and will have grizY magnitudes available in a further publication. We present software for simulating our observational biases for comparisons of models to our detections. Initial inferences demonstrating the catalog's statistical power are: the data are inconsistent with the CFEPS-L7 model for the classical Kuiper Belt; the 16 "extreme" TNOs (a>150au, q>30au) are consistent with the null hypothesis of azimuthal isotropy; and nonresonant TNOs with q>38au, a>50au show a significant tendency to be sunward of major mean-motion resonances.