Federal Environmental Web Tracker
https://envirodatagov.org/federal-environmental-web-tracker-about-page/
The Federal Environmental Web Tracker is a project undertaken by the Environmental Data and Governance Initiative that monitors "thousands of federal government webpages to track changes under the Trump administration" and "makes these changes publicly available and searchable." The intent is for the site to be updated on a regular basis. You can access the Tracker directly via https://envirodatagov.org/enviro-fed-web-tracker/.
The Nation's Data at Risk
https://www.amstat.org/the-nations-data-at-risk-year-two-ongoing-monitoring
The American Statistical Association and George Mason University have been monitoring developments at federal statistical agencies, including developments such as cuts in data-collection programs, decreases in budgets, and staffing changes. This site is part of a broader ASA/GMU effort to assess the well-being of federal statistical agencies. See https://www.amstat.org/policy-and-advocacy/assessing-the-health-of-the-principal-federal-statistical-agencies for additional information.
"STAT is Backing Up and Monitoring CDC Data in Real Time"
https://www.statnews.com/2025/02/14/tracking-cdc-data-changes-trump-executive-order-targets-gender/
STAT News has been analyzing removals of datasets from the CDC's open data platform at https://data.cdc.gov/. STAT has been tracking both removals and restorations of data, including reviewing restored data for changes in those data. In addition, STAT has also been creating back-up copies of data that were removed from federal sites.
U.S. Government Information: Weekly Roundup
https://ucsd.libguides.com/usgov/roundup
The UC San Diego Library has been montoring federal government statements and releases. The site casts a wide net and is not focused just on data sources, but it does tracks changes to government websites and post links to commentaries about the implications of removals of data from government sites.