Hi, Here is few ressources to find Single-Cell datasets for human and different species :

• https://data.humancellatlas.org/
• https://singlecell.broadinstitute.org/single_cell
• https://www.ebi.ac.uk/gxa/sc/home

If you don't find what you want, I advice you to search an article related to your research subject and find accession of data in the materials and methods (GSEXXXX for Gene Expression Omnibus for example).

Are you looking for something more precise than a big dataset like an organ to study or cancer specific ? Generally, if you want to process scRNA-Seq data, it's easier to get the ouput of alignment tools with these 3 files :

• matrix.mtx
• features.tsv
• barcodes.tsv

After downloading it you can process them with Seurat : https://satijalab.org/seurat/