I finally got around to examining the Rainbow disks I won last September.
They have Windows for Rainbow that looks fairly standard "7 disk" collection (the one that has both VAXmate and Rainbow drivers that people here have reported issues with).
Utility disks for the DEC (3 different kinds), CHS, DM220 and ACT winchesters. I'm unfamiliar with ACT, but I think it was some custom thing because there is also CP/M for ACT and MS-DOS for ACT "master" disks.
And a lot of different application software. I'll see about organizing it when I have time to read all these in.
Oh, and a lot of blank disks that might be the personal backup of somebody's computer from 1986 (the labels are unclear, and some labels have fallen off due to the march of time.