Applications of Gradient Descent Methods

Question

I'm trying to find applications of the batch gradient, stochastic gradient, and mini-batch gradient descent method. Most applications (on Google Scholar) seem to be too theoretical or, in the area of deep learning of which I don't know much. (I only know the basic idea of artificial neural network.)
I found an example, which is a linear regression model using the batch gradient descent method for parameter estimations, but cannot find other easy examples.
Are there any other applications of those methods, or case study? If so what would those be? It will be great if those applications are understandable for a masters student. Thank you in advance!