Hi @PAJenRed,
You can use the _CommentCount field in a HTTP request. That field does not seem to be available in normal actions. However, you can workaround that by using the RenderListDataAsStream method.
Below is an example
URI
_api/web/lists/getbytitle('@{variables('ListName')}')/RenderListDataAsStream?View=@{variables('ViewID')}&FilterField1=_CommentCount&FilterOp1=Geq&FilterValue1=1
Body
{"parameters":{"__metadata":{"type":"SP.RenderListDataParameters"},"RenderOptions":1463815,"AddRequiredFields":true,"RequireFolderColoringFields":true}}
