I have created a small SPARQL query service for Wikidata history. It
is in a very early stage.
It currently stores metadata about each Wikidata item or property
revision (contributor, timestamp, entity edited, previous/next
revision of the given entity) and a part of the revisions content
(wdt: direct claim relations and redirects). It allows to query the
triples added and removed by a revision and query the full state of
the Wikidata graph after any revision. The data loaded covers a range
from the creation of Wikidata to July 1st 2018.
The help page : https://www.wikidata.org/wiki/Wikidata:History_Query_Service
The query UI : https://wdhqs.wmflabs.org/
I hope it will be useful for doing interesting researches around Wikidata.
Feel free to email me if you need help with it. If it is useful for
many people I hope to be able to take time and get storage space to
load more recent data and the missing parts of Wikidata items