[mheathr]

There are at least 6 that are explicitly used (there are more in practice but they are mostly transparent of rare and even realizing this will require reading some of the more esoteric documentation): visual line mode, insert mode, ex mode, normal mode, replace mode, visual block mode.

[lutusp]

Thanks. I got tired of trying to use vi/vim before fully plumbing the depth of these additional modes.