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.
I upload files to Wikimedia Commons. Most of these have been linguistic vector image maps I've created, usually where no map existed before; my own photos of notable landmarks; and third-party free-use medical images under CC-BY or 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)