I only use 4 types of brushes in my daily makeup routine. Not the same exact brushes, but the same types. For applying my foundation I use a flat top powder brush for the best coverage. For my eyeshadow application I prefer to use an eyeshadow brush, I may use 2 or 3 of these depending on how many colors I use. Then for the crease I prefer to use a thinner brush like a concealer brush, and then I use a clean fluffy brush for blending it all together. It doesn’t matter what your brush is called, what matters is the shape. For my eyes- the concealer brush works best at getting into the crease if my eyes. For some a contour brush may work better, but my eyes are smaller and the crease brush gets into the smaller spaces much better.
I think the key to finding the right brushes is experimentation, buy an inexpensive set and play around with the application, and develop a routine with those brushes. Also make sure you take proper care of your brushes. Spot clean them between application with alcohol to disinfect and brush cleaner. I use baby shampoo to clean my brushes at least every two weeks. I also use conditioner so they stay nice and soft. make sure to dry then bristles down as to not let water into the ferrules. This has been a long and winding post about brushes lol.