Much of the following osmotic pressure data was measured and curated by the late Dr. Don C. Rau of the Laboratory of Physical and Structural Biology (LPSB) at the National Institute of Childs Health and Human Development (NICHD). As of December 2016, the osmotic stress resource page appears to be no longer available as well as a companion site at Brock University. The LPSB data below is from a copy I made of that site around September 2015. I plan is to slowly post the data from that site here. If you are looking for specific osmotic pressure data, please feel free to email me with your request and I will try to move your request to the top of the queue.
Update (Apr. 2021) -I am working towards moving the osmotic pressure data towards a JupyterLab notebook for analysis. The pages will be implemented and shared using Google's Colaboratory. You probably cannot run the linked Colaboratory notebooks. But you should be able to download the ipynb file and run it locally (or on your Colab account). I have also posted screenshots of the LPSB pages that I managed to capture. I will also eventually post CSV files with the data and calculations.
Probably one of the more difficult ideas to master are the different ways of expressing osmotic pressure and the important difference between molality and molarity. This is important because the LPSB data is reported as either in log10P (dyne/cm2) or in osmolals.