Perplexity allows users to access multiple AI models with cited sources for verification. Google Docs enables collaborative document creation and editing with features like commenting, automatic cloud saving, and offline access. Notion serves as a hub for to-do lists, notes, documents, and project management, with AI capabilities for transcribing and summarizing notes. Microsoft To Do offers a user-friendly interface for creating to-do lists, setting reminders, and collaborating with others, while syncing across devices. Proton Drive provides end-to-end encryption for file security, automatic backups, and additional security features like PIN or biometric protection and secure file sharing options.