You can tell when a VCF file contains a phased genotype as the delimiter used in the GT field is a pipe symbol | e.g
#CHROM POS ID REF ALT QUAL FILTER INFO FORMAT HG00096
10 60523 rs148087467 T G 100 PASS AC=0;AF=0.01;AFR_AF=0.06;AMR_AF=0.0028;AN=2; GT:GL 0|0:-0.19,-0.46,-2.28
The VCF files produced by the final phase of the 1000 Genomes Project (phase 3) are phased. They can be found in the final release directory from the project and in the directory supporting the final publications.
Some other studies have also produced phased versions of their calls. These include the analysis of high-coverage data across 3,202 samples on GRCh38 completed by NYGC. Multiple sets of VCFs are available, including phased VCFs, linked to from the page for that collection.