1. Time series based forecast based on revenue (the one OP is referring to). All the statistical time-series models come here. I primarily used H2O.ai for this.
2. Conversion based revenue forecast (input -> pipeline, output -> revenue). This proved to be quite tricky as there was a time lag between pipeline creation and revenue conversion
3. Delphi-method: Got the sales/pre-sales folks on-ground to predict a bottom-up number and used that as a forecast.
Finally, I combined them by applying weightages to the above approaches - based on how accurate they were on the test dataset.
IMHO, Like many of them have pointed out - the model/assumptions are more important than the library. The job of a data scientist is to make the prediction as reliable and explainable as possible.