Here is a list of popular restaurant POS (Point of Sale) systems used by businesses in the food service industry:

1. Toast: An all-in-one restaurant management platform that includes POS, online ordering, inventory management, CRM, and reporting features.
2. Square POS: A versatile POS system that offers payment processing, inventory management, employee management, and customer engagement tools.
3. Lightspeed Restaurant: A cloud-based POS system with features like tableside ordering, menu management, employee scheduling, and analytics.
4. Revel Systems: A scalable POS platform that offers features such as order management, inventory tracking, tableside ordering, and loyalty programs.
5. Upserve: A comprehensive POS and restaurant management platform that includes features like tableside ordering, inventory management, staff scheduling, and reporting.
6. ShopKeep: A user-friendly POS system with features such as sales reporting, inventory tracking, employee management, and integrations with other business tools.
7. TouchBistro: A POS system designed specifically for restaurants and bars, offering features like tableside ordering, menu management, split checks, and reservations.
8. NCR Aloha: A robust POS solution that offers features like tableside ordering, inventory management, online ordering, loyalty programs, and reporting.
9. Micros (Oracle Hospitality): A widely used POS system with various modules to manage different aspects of restaurant operations, including point of sale, inventory, and kitchen management.
10. Clover POS: A versatile POS system that caters to various industries, including restaurants. It offers features such as order management, payment processing, and inventory tracking.
11. Maitre’D: A POS system designed for restaurants and bars, offering features such as table management, order entry, kitchen display system, and loyalty programs.
12. Squirrel POS: A feature-rich POS system that caters to the unique needs of restaurants, offering tableside ordering, inventory management, reporting, and integration options.

These are just a few examples of restaurant POS systems available in the market. When choosing a POS system for your restaurant, consider factors such as your specific needs, budget, scalability, ease of use, integration capabilities, and customer support to find the best fit for your business.