In a nutshell, most issues since 1976 have been digitized. The era from 1958 to 1976 still has substantial gaps.
Maybe that will start getting filled in now that the Legion has their own series again, the first since things shut down for them in 2013, 6 long long years ago.
My wife was at work Saturday, and when I saw the Comic Vine chronology a fan posted only goes to 1998, I…stole his work and added to present, then checked out DCU
The Chronology Legion Sheet has been updated with the new digitized issues announced for this week!! Also please note the new location of the file, Legion minutia fans!!!
The Google Sheet Chronology of Legion of Super-hero comics with DCU digitized issues noted has now been updated noting the most recent Legion reading that has been completed! The six year reading mission continues!!