Where to learn about music production plugins with free tutorials?

[JustinA]

There are thousands of music production plugins available, both free and paid. Where can I find good tutorials that explain what different types of plugins actually do and how to use them effectively? Looking for resources that cover EQ, compression, reverb, delay, saturation, modulation, etc. in a way that's not too technical. Bonus if they focus on free plugins or explain concepts that apply to any plugin of that type.