If it is about Tableau and other BI tools (Cognos, Microstrategy, Pentaho, Domo, Qlikview, Power BI) it lives here.
Analyzing and Visualizing Data with Power BI - The eDX course is free and good as a first overview, but doesn't go in-depth on DAX or M.
EnterpriseDNA - have a good/great YouTube channel for specific examples but also have a Complete Beginners training for Power BI and one for DAX which are good groundings and free.
The Definitive Guide to DAX (Business intelligence with Microsoft Excel, SQL Server Analysis Services, and Power BI) by Marco Russo and Alberto Ferrari
PowerPivot and PowerBI The Excel Users Guide to DAX by Rob Collie and Avichal Singh
M Is for (Data) Monkey: A Guide to the M Language in Excel Power Query by Ken Puls and Miguel Escobar
PowerPivot Alchemy: Patterns and Techniques for Excel by Bill Jellen and Rob Collie
powerpivotpro - a general go to source. You tend to find a lot of the other industry experts contribute or help out in the comments.
sqlbi - Marco Russo and Alberto Ferrari covering DAX/SSAS/MDX
Excelguru - blog by Ken Puls (M and Excel related topics)
Kasper on BI - All about BI, Modelling, DAX and MS BI by Kasper de Jonge
Big Query (BQ)
How does one get started with BigQuery? @simoahava answered "Take the SQL track on Mode Analytics. The From Data To Insights specialization on Coursera has quite a bit of BigQuery lessons (it’s self-paced and you’re in charge of how much you want to apply your learnings in the labs), but it does require a solid grasp of SQL basics.
That’s the only course for BQ I’m familiar with - and it was pretty good in diving into its idiosyncrasies."
@simoahava then says "The Data Engineering on GCP specialization on Coursera also has BQ lessons but they’re more about how BQ fits into the entire data pipeline and less about how BQ works. But the idiosyncrasies aren’t that far removed from standard sql. It’s the columnar table format that requires the biggest mind shift from working with relational tables. Get well acquainted with how to work with structs and repeated fields, and how analytical window functions work. These are covered in the Coursera specialization."