RE: List of major modes?

[Drew Adams]

    > unfortunately minor-mode-alist contains stuff to be
    > shown in the mode-line, so we're not excluding minor modes
    > that don't display anything in the mode line

    > The only solution I can see is to patch define-minor-mode -
    > as a last resort.

    Not all minor-modes use define-minor-mode.  One way or another, some
    stuff will slip through.

I agree - some stuff will slip through. I don't think you'll find a 100%
solution for excluding minor modes. There is too much overlap between the
conventions of defining major and minor modes, and too many ways to define
each.

Recent Emacs versions have `minor-mode-list' (not alist), a list of all
minor mode functions. There is no guarantee that it will be complete,
however. It is fed by `add-minor-mode'.