<I’ve added links to free Intellivison ROMs to the OP>
edit: @recompile I think there is a good chance that 4-Tris will end up as part of the built-in RetroArch free content downloader in the near future (mostly because of its GPL license).
After thinking some more about @te_lanus 's situation, would it make sense to have a standard testing & troubleshooting ROM for users?
If you agree, I’d suggest that 4-Tris could be a good recommendation as the first ROM for people to try when they’re setting up FreeIntv or troubleshooting it. It’s easy to get already, and soon it may even be available automatically from within the RetroArch interface, at least for RA and Lakka users.