Rosco used to sell something called the Jungle Safari kit. It had CTO, CTB, plus-green, and plus-magenta gels in full, half, quarter, and eighth values. Combining different gels could balance flash to pretty much any ambient. I see they list a "color correction kit" now that has only blue and orange (CTB and CTO.) Too bad.
For balancing flash to fluorescent, it really depends on which type of bulb is in the room. Lots of rooms on our campus use Warm White Fluorescent, which is about 3600K and has a color correction of ~24 magenta in Lightroom. Balancing a flash requires a Half or Full CTO and about a 1/2 so Plus Green (green filter.) That gets in the ballpark.
Other fluorescents might be 4000-4400K, or even "daylight" at 5000K or so. Almost all of them will require some green over the flash to balance, but different amounts of orange, or none at all. The key is to test, then test again, and keep copious notes.
Also note that different flash units will require slightly different filter packs.