I just found that such a resource exists for philosophy, in case it is of interest to others: Meta-Encyclopedia of Philosophy.
On reflection, I guess it makes sense that the philosophers would be among the first to "go meta".
While Wikidata isn't complete it has lists of other existing encyclopedia articles on a given topic. Whenever you are at Wikipedia you can click on Wikidata item on the left side and get taken to Wikidata. The Wikidata item lists a variety of external ids for the topic in other sources.
I think it would be great to have a browser plugin that whenever you visit a page about a topic that has external id links on Wikidata it shows you links to all other pages about the same topic. Ideally the addon would also provide an easy way to add new links. If you have two browser tabs on the same topic open where both conform to a Wikidata formatter url pattern it while only one is linked in Wikidata it could give you an easy way to link the two together.
This is a sidepoint, but I'd be interested in hearing more about Wikipedia's "increasing signs of ideological uniformity". I wasn't aware that it was biased, and I'm not sure what direction the bias is in.
This is my anecdotal impression as a long-time Wikipedia editor (I started contributing in 2003). I can't offer concrete evidence other than my testimony, because this impression was formed in the course of observing subtle instances of bias on countless occasions, rather than encountering any one egregious incident. (Though on reflection I can cite two not-so-subtle examples illustrative of the phenomenon I have in mind: first, the labelling of cryonics as "quackery"; and secondly, the blacklisting of Econlib.)
The biases I noticed are in the left-wing and "skeptical" directions (meaning by the latter something like what Eliezer calls "traditional rationality", as opposed to the "Bayesian rationality" folks in the rationalist and EA communities generally endorse). Think of it as Wikipedia moving slightly in the direction of RationalWiki.
Another example I just discovered: Wikipedia classifies Quillette as an unreliable source; by contrast, Vox, The Nation, Mother Jones are all considered reliable sources. I don't often read Quillette, but my sense is that a criterion that generates this classification can't be defended as unbiased.
Whether a source is classified as reliable or unreliable can shape the content of Wikipedia articles in major ways, because only statements backed up by sources deemed reliable are admissible. If the list of reliable sources is skewed in a particular direction, so will be the articles.
With Wikipedia showing increasing signs of ideological uniformity, I thought I should try to diversify my consumption of reference material. A potentially very useful tool for this purpose would be a "meta-encyclopedia", i.e. a place where users can find a list of all existing encyclopedia entries on a given topic. Questions:
1. Does something like this exist?
2. If not, what are the closest substitutes?
My current method is to simply do a Google search for the topic of interest followed by the word 'encyclopedia', e.g. 'comparative advantage encyclopedia'. This method is already quite useful, with a much lower false-positive rate than I would have expected, though I feel there's still considerable room for improvement.