Microsoft Office Excel - Microsoft Office Excel is a commercial spreadsheet application.
Impler.io - Powerful CSV & Excel Import experience for SaaS 🚀 Save months building data import experience from scratch 💰
Google Sheets - Synchronizing, online-based word processor, part of Google Drive.
csvbox - Spreadsheet importer for your web app, SaaS or API
Apple Numbers - Numbers lets you build beautiful spreadsheets on a Mac, iPad, or iPhone — or on a PC using iWork for iCloud. And it’s compatible with Apple Pencil.
Layercode UseCSV - Add CSV import functionality to your app in minutes