I don't think there can really be such a thing as "standard Maya hotkey mappings" for several reasons like:

- Maya offers several different ways of accessing the tools other than hotkeys, a tool one user might prefer to map to a keyboard shortcut, another user could prefer to add it to a shelf, or marking menu or some kind of scripted toolbox or a HUD button even.

- There are going to be tools that people don't have in common because they use Maya for different purposes.

- Even if the end product is basically the same, people can have differing workflows and many instances the tools themselves are custom.

Well you see where I'm going with this. It really does come down to whatever you're comfortable with and what works. My personal setup uses custom marking menus that I can cycle through and they are also context sensitive. Trying to remember hotkeys for even half of that or having to skim through shelves would drive me insane.