hg38/GRCh38 Genome Build
The reference files were downloaded here. This build include an additional index file that is required to flag alternate contigs as described here.
FASTA
Homo_sapiens_assembly38.fasta
Homo_sapiens_assembly38.fasta.fai
Homo_sapiens_assembly38.dict
Burrows-Wheeler transformed
Homo_sapiens_assembly38.fasta.64.bwt
Homo_sapiens_assembly38.fasta.64.ann
Homo_sapiens_assembly38.fasta.64.amb
Homo_sapiens_assembly38.fasta.64.pac
Homo_sapiens_assembly38.fasta.64.sa
Alternate contigs
Homo_sapiens_assembly38.fasta.64.alt