Hi Hunter!
The best and accurate way to familiarize yourself with all the components of the Project Management Plan is to check PMBOK 6 (4.2.3.1 section) which can be downloaded from pmi.org
In a nutshell, there are:
Subsidiary management plans: Scope Management plan, Requirements management plan, schedule, cost, quality, resource, communications, risk, procurement, stakeholder management plans.
Baselines: scope, schedule, cost.
Additional components: change management plan, configuration management plans, performance measurement baseline, project life cycle, development approach, management reviews.
All other project documents are not part of the project management plan.