The use of parameter tables is a well-known technique in Power Query. It involves using a table from the current Excel workbook to hold various parameter values that are read using a Power Query query, and these parameter values are then passed to another Power Query query to control how it behaves. Ken Puls has a great post describing all this here, and similarly a lot of the demos in my video on on building a reporting solution in Power Query involve reading values from a table which are then used to filter data in a SQL query.