I have a general question: Are the bundled plugins with the ne Tikipedia applied specifically for each page or global (for all pages)?
They can be used on any wiki page, with any theme.
They are page-specific in the sense that they must be inserted into a wiki page at a particular place in the page.
Wiki plugins, it seems to me, are basically of two types: the first is just to extend wiki syntax, especially for when HTML isn't activated for wiki pages. The Tag, Split, and Div plugins are good examples of this type.
The second type of plugin displays additional content, often from Tiki's database. The Module plugin (displaying Articles, etc.) is an example of this type.
The uses of wiki plugins and dynamic content blocks overlap, especially when the wikiplugin is the "display other content" type. But I think one way to keep the two distinct is that plugins are specifically for wiki pages, and dynamic content blocks are primarily for use in templates. Of course when used in templates, the (probably same) content appears every time the template is used. A wiki plugin can display unique content every time it is used, depending on what parameters are input for it and so on.
There isn't a complete list anywhere. Seems like people make plugins to meet a need at their own site and don't necessarily try to distribute the plugin. The mods.tikiwiki.org site was at one time heading toward that kind of function, but development there stopped. It'd be a good thing to get going again, encouraging people to contribute their plugins, modules, and so on.