I normally come across the pages I edit in my everyday research. These often include articles that were last edited a long time ago, stubs, articles without sources and other obscure articles.
Other
CC-BY-SA licences. I've also uploaded various other miscellaneous free-use files and own diagrams, and sometimes I've vectorised
existing maps, cropped photos or otherwise improved existing files.
I've also edited and created some articles on Wiktionary and the French Wikipedia and edited some others on other wikis.
Gadgets I recommend other users enable (as of 2020)