Product Councils
Form product councils for each of your main product areas. Hold a monthly, 90 minute meeting with 5-20 stakeholders where you share progress, present priorities, get feedback, and build buy-in all at once.

This issue covers one of my go-to plays. I use it in at least half of the companies I work with. It's controversial, but I find it one of the most efficient ways to build and maintain stakeholder alignment.
Use this play when:
People outside of product are frequently calling meetings to debate development priorities. Executives raise the priority of single projects one at a time without considering tradeoffs and opportunity cost. Stakeholders feel priorities are up for debate all the time. Prioritization decisions that seem firm are continuously questioned, re-debated and re-analyzed.