While the so-called "DEI" pages/information have been, by far, the most heavily purged content, we've seen similar actions against many other areas of the federal web. While there is not, to my knowledge, anything approaching a comprehensive accounting of pages that have been removed or altered, a February 2 New York Times article reported over 8000 pages had been taken down at that point. A few examples...
The DOJ database of defendents charged in federal court for January 6 activities (via Internet Archive)
The Climate and Economic Justice Screening Tool (via Internet Archive; an "unofficial copy" was subsequently created by Public Environmental Data Partners)
The United States Agency for International Development website went dark on January 27, 2025 as the new administration claimed they were shutting down the agency. Currently, this banner is the only available content; see the Internet Archive for the scrubbed pages.
Data removal was of particular concern to many, as the federal government is the main producer of public data in the U.S. and this data cuts across a vast array of subjects. The information below is from the Center for Regional Economic Competitiveness:
The Department of Homeland Security's FOIA Library is an example of altered rather than fully deleted content. The highlighted items below are no longer on the live FOIA website, but were moved to a separate content archive. They can also be found in the Internet Archive.
The database tracking misconduct by federal police officers was shut down. The database itself was never available to the general public, but the public "about" webpage is available via the Internet Archive.