The latest batch:
Several of these were recommendations from panels at the recent WorldCon. The Dragon Never Sleeps was recommended as being Banksian. Gallun was recommended during the 1938 Retro Hugos panel. The Mirage was recommended during the infodump panel; I don’t know why I hadn’t already got it, given how brilliant Sewer, Gas, Electric is.
The presence of the Randall Munroe needs no explanation.