Special:UnconnectedPages, specifically some high-priority items where there's useful metadata or a high probability of an existing item:
Pages that exist in other languages: useful for populating inter-language links
Scientists: there's a good chance a Wikidata item with their ORCID and publications already exists
Authors: they probably have a VIAF ID, and since VIAF syncs with Wikidata, these can be useful for libraries. Additionally, they provide a good way to prevent duplicates.
Some heritage buildings: the NRHP hasn't been bulk-imported, but some countries' have (the UK and Romania among them).
Category:Pages using infobox person with unknown parameters: in which some people figure you can throw any old thing into infobox parameters, and some people just make typos. Note that the sort key of the category is the unrecognized parameter name, so if you go through in order you'll probably get typos of the same thing over and over again.
This query, which gives unsourced pages where the talk page has never been created; useful for finding seriously underlooked pages. I've been PRODding some and tagging others with appropriate WikiProjects so that hopefully someone with subject-matter knowledge will notice them.
There are a surprisingly large number of inline IMDb links; these are almost never appropriate. There's no link associated with this one because even getting an approximate count of where they're removable requires cross-referencing Quarry queries with Wikidata, and ideally doing some wikitext parsing to filter out some false positives; when I get around to it maybe I'll create a bot report out of it.
Replacing bespoke "citation needed" tags with {{Citation needed}}. I suppose there are new editors who just try to replicate the superscript and link and don't realize that the template gives additional benefits: a tracking category and support by tools like Citation Hunt. There's a decent search query for this, but I've lost track of it. Some of the simpler cases would make good AWB tasks.
