“Sequence Read Archive (SRA) data, available through multiple cloud providers and NCBI servers, is the largest publicly available repository of high throughput sequencing data.”
Downloading sequence data from SRA can be a little bit complicated though, due to the database structure and that files are stored in SRA format and need to be converted (to fasta, fastq, etc).
The SRA toolkit allows files to be downloaded as a batch, using the project accession number, and also convert to the correct format at the same time.
To install SRA toolkit, follow these instructions:
https://github.com/ncbi/sra-tools/wiki/02.-Installing-SRA-Toolkit
To download data fasta files using project or biosample accession numbers:
https://github.com/ncbi/sra-tools/wiki/08.-prefetch-and-fasterq-dump
You can also use SRA Explorer to view all files in a project and download all or some of them.