https://www.computerhistory.org/tdih/ https://www.pyxll.com https://www.mathpax.com/myposts/software/pyxll/ http://omz-software.com/pythonista/ https://www.mathpax.com/myposts/software/pythonista/ http://www.adaptedmind.com/ https://www.pythonanywhere.com/ https://notebooks.azure.com/ http://jupyter.org/ http://www.3blue1brown.com/ https://www.enthought.com/product/canopy/ https://www.numberphile.com/
Here is a beautiful website by Grant Sanderson. 3blue1brown So many exciting insightful mathematics presentations. The craft and artistry are as impressive as the mathematical concepts. Take a look — even if you think you know the material — you will see a few new gems (I bet).