Some of the tools and techniques for the PMI process of plan quality management are listed in the PMBOK as "additional quality planning tools" (section 8.1.2.7). The tools listed are brainstorming, force field analysis, nominal group technique, and quality management and control tools.
Related (other quality planning tools and techniques): cost-benefit analysis, cost of quality, seven basic quality tools, benchmarking, design of experiments, statistical sampling, meetings