When you're running up & down the steps of a drilling rig in the Gulf of Mexico, you don't want to carry a lot of baggage! So I always had two Vivitar 283s with me for "all-around every-day emergency" use. There were (actually "are", you can still get them & I still use mine) amazingly versatile units. Accessories include filters for WA & telephoto coverage, a remote cord for moving the sensors off the flash, and a VariPower sensor that can seamlessly dial down the power 5X. I love them!
This office was typically small with typically crappy green fluorescent lighting. I used flash on-cam set at the “right” exposure and 1 high to the right as a hot, accent light.
The pic below is a dupe of a cull slide, one where the lighting wasn’t just right, but the only one I could find in my files. Still, it illustrates the point that you don’t have to go elaborate lengths to improve the situation by a few hundred per-cent.
EDIT: There's a lot more added to this thread, so be sure to read the whole thing!
20mm f/3.5 Nikkor & 2 Vivitar 283s.
You might still be able to find filter packs on eBay. There are two & they come in color & light modifying.