I'm not sure about "terabytes" but yes, the new administration has edited the whitehouse.gov domain, including the open subdomain.
New administrations across all levels of (U.S.) government, particularly around elected officials, wipe domains and start a new.
While there are many things going on currently with the Trump administration that are bad ...
You can start with http://everypolitician.org, here's a link to the UK data on github.
At Unigraph we've merged everypolitician's with data from Wikidata and Freebase, so you can conveniently query it, for example "get the facebook, twitter and wikidata ids of Adam Holloway, the fb and twitter urls and the party he is member of".
Reach to me for an API ...
National GIS Resources
NHGIS has historical data for the United States
Great Britain Historical Geographical Information System (GBHGIS)
The Great Britain Historical GIS (Main)
GBHGIS Data Access
National Heritage List for England (NHLE) Listing Data
The US National Historical GIS
The China Historical GIS
Chinese Civilization in Time and Space
The GitHub repo 2016-campaign contains
campaign speeches given by Hillary Clinton and Donald Trump during the 2016 presidential campaign.
[and] the text of the three presidential debates, separated by speaker, in the presidential-debates folder.
The repo owner will add speeches as the occur.
Google Consumer Surveys is very open with their data. You can see their reporting here and the archive of all their polling (with CSVs containing each individual response) here.
Otherwise, most pollsters keep their raw data close to their chest, and only release their analysis of their data. Check out FiveThirtyEight's national poll listings, which include ...
There are data available from Bundeszentrale für politische Bildung. The pure numbers are probably not copyrightable and therefore Open Data.
EDIT: I answer to the headline. but not to the text. I won't delete my answer for now, altho it does not fulfil the data request stated in the text.
@twiplomacy's world leaders list is a start but more importantly, they have a number of curated lists.
Every Politician has social links for politicians.
List of current heads of state and government/twitter-list - Archiveteam
Politwitter Lists (Canadian Gov)
US Senator Twitter Accounts, 115th Congress (...
One source for the US (2018 election) is
The first of its kind, this collection consists of every campaign logo from the 2018 election for United States Congress. The archive is a tool to explore trends and typologies that reveal themselves only when viewed in aggregate.
(they offer a bulk download on demand, and I'll ...
This would certainly be an interesting dataset to see, but as far as I am aware, municipal governments act in such silos with frequently changing leadership that there is no authoritative resource that breaks down the racial makeup of mayors and council members on an annual basis,.
That said, it is certainly a dataset that could be put together almost ...