This free online tool allows to generate JSON dataset. You can generate multiple JSON files exported to a zip archive. No limits. No registration.
Mockaroo - A realistic data generator to test your app
Modern CSV - A CSV editor/viewer
JSON Generator - Create mock and sample JSON using a powerful template syntax
Rons CSV Editor - Rons CSV Editor / Now Rons Data Edit
Sbored. - Discover things to do in your free time
ReCsvEditor - Csv / Tsv / Delimited file editor. Supports for very large Files.