NCBI taxonomy is my go to for this, search the species of interest in NCBI taxonomy and the go up lineage by lineage for example https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=301 . You can set the filter "has genome sequences" and then traverse the lineage hyperlinks.

Since this is a bit of an open ended question here is one possible answer. Visit NCBI's taxonomy browser. Search with the name of the organism. You should see all related species.

There will be a Lineages line with a set of clickable links towards the top of the page. That will allow you to go up the chain of organismal classification to broaden your selection.