Heads of Government since 1870
Thomas Brambor and I have compiled the Heads of Government Dataset, which provides summary information about the ideological orientation of heads of government in 33 countries since 1870. The dataset is described in our article "The Ideology of Heads of Government, 1870–2012" (see here).
The version of the dataset that is available via the link above ends in 2013. Preliminary data including the period 2014–2017 are available here in leader-year format. A full version, in both leader-year and country-year format, will be published here as soon as it's ready.
Information Capacity since the French Revolution
Thomas Brambor, Agustín Goenaga, Jan Teorell and I have compiled the Information Capacity Dataset, which provides comparative, historical data on five information-gathering and information-organizing activities among states: the introduction and implementation of a national census, the introduction of civil and population registers, the establishment of a permanent state agency tasked with processing statistical information about a country's territory and population, and the regular publication of statistical yearbooks. The dataset is described in our article "The Lay of the Land" (see here).
Immigration Policies in Europe, 1880–1920
For our article "Immigration Policy and the Modern Welfare State, 1880–1920," Sara Kalm and I compiled data on immigration policies in a selection of Western European countries in the late nineteenth and early twentieth centuries, complementing data on other countries that have been compiled by Margaret Peters and following Peters's coding conventions. The new data, which cover Austria, Belgium, Denmark, Finland, Italy, Norway, and Sweden, are available here. For variable definitions, see Peters's codebook, which is available here.
Several other datasets that I have relied on in my work are available as replication data files via the Research page.