Nadel at ETH offers both a Certificate and a Masters Degree in Advanced Studies in Development and Cooperation.http://www.nadel.ethz.ch/education.html
MIT offers an online micro-masters by world leading development economists, worth 1 semester of courses (can be taken at flexible speed). Interested successful graduates are automatically admitted for a full Masters Degree at MIT: https://micromasters.mit.edu/
General Interest
"Poor Economics: A Radical Rethinking of the Way to Fight Global Poverty" by Abhijit Banerjee und Esther Duflo
"More than Good Intentions" by Dean Karlan and Jacob Appel
Effective Altruism Switzerland have many activities working towards effective international aid, etc.:
https://ea-foundation.org/ Contact: jonas.vollmer@ea-stiftung.org