I don't see why these are all split up. Separately, they don't really make any difference. In general, we're talking about "HTML Lists" and not an ordered or unordered list specifically. Whether or not it is ordered or unordered tends to make no difference with the questions, since oftentimes it's a CSS-related question about lists, which all use
list-style and its sub-properties, or about nested lists, which aren't specific to either one (and usually get tagged along with nested-lists).
Going of the idea of being an expert in the tag, if you are an expert in any one of them you'd most definitely be an expert in all of them. A list item is part of a list, so there's definitely no point in having that separate tag. I propose that all of these tags be merged and/or synonymized into one single tag html-lists (which makes most sense to cover them all). The tags that currently exist:
It'd be preferable that synonyms be created for these so that users typing in "ul", "ol", or "li" can easily find the correct tag.
Update: I have gotten the tags to a place where unordered-list and ordered-list are currently suggested as synonyms of html-lists, but now we need either 4 people who have 5 votes in that tag or a moderator to push them through. I've also been going through the list of questions that are tagged with both html and list and converting to the correct tag.