Following are most imported and highly desirable products for QA Life cycle.

Mercury Products:

WinRunner for Functional Testing

Quick Test Pro for Functional Testing

Load Runner for Load Testing

Topaz for Online Monitoring

Test Director - Test Management and Bug Tracking Tool.

Segue Products

Silk Test for Functional Testing

Silk Performer for Load Testing

Silk Central Test Manager - Test Management Tool

Rational Products

Rational Functional Tester

Rational Manual Tester