If you're just starting out in RevOps, what reports or metrics should you be preparing for your Head of Sales?

Revenue
Forecast
Pipeline growth
Conversion rate
Wind rate
Pipeline coverage

These metrics should be available for every sales rep so that the Head of Sales can compare their performance. 
That helps to identify their individual talents and training needs. 

An understanding of pipeline management forecasting and standard metrics like pipeline coverage, deal volumes, cycle time, stage progression, average sales prices, forecast revenue by forecast stage, and forecast ranges. Having sales activity and reps productivity reports help prove deal progression and I’d show the conversations of win rates/loss reports.
However, if the underlying data is not proven, accurate, and adopted, then it's garbage and you're going to be making the wrong decisions.