Custom triggers in Dynamics 365 Marketing (Customer Insights - Journeys) have recently became 1000 times better with the ability to include ‘Entity references’ - a way of making an entire record and all its associated records (up to 5 levels ‘deep’) available through a single trigger attribute. It works exactly the same as the ‘Contact‘ or ‘Lead’ in a trigger works, but for any table/row you choose.

This make all the data available in the trigger journeys for branching and emails for conditional content and personalisation. And you can have lots of these!