Best option: don't use colour unless you have a specific need for it. Many years ago I worked as a typesetter for a while in the jobbing commercial print industry. Most of the clients did not want to pay for a colour print job due to the set-up costs, so the jobs tended to be black and white or two spot colours.
Also, I've done any amount of documentation work where the output device was a black and white laser printer.
Unless you have a good sense for colour attempting to play amateur graphic designer is probably more trouble than it's worth. Start with black and white reports, perhaps with one or two highlight colours. If you find an overall colour scheme you like, you can use it as a standard format, but keep it simple. Otherwise, you're really just adding Chart Junk, which is a bad thing.
If you really need colour, use it sparingly, and avoid reversed out headers (light text on a dark background). Some suggestions for sparing colour use:
Light pastel shades (no darker than something equivalent to a 10-20% gray half-tone) on headers or the left-most column. Only shade the left-most column if it is relatively narrow. This sort of header with a light bar down the left side will frame a report.
Alternating bars of approx. 5 lines or so. 5 lines in a plain white background and 5 lines in a pastel shade. This should be lighter (equivalent to a 5-10% gray) than the shade you would use in headings described above. Only use this if the bars are equal size - it looks ugly if the bars are different heights.
Highlighted values (if you have numbers that are alterted if out of a certain range) in an alert colour. This might be quite useful for KPI reports.
Charts - use lighter shades rather than bright primary colours for printed charts unless you are doing line graphs, in which the lines should be relatively thin and darker colours like maroon or navy blue. Leave any borders, pips, axes and labels in black.
Avoid graphical decoration for its own sake unless you are actually a competent graphic artist. Amateur graphic design got a well-deserved bad rep in the 1980's and 1990's with the advent of desktop publishing. Keep the reports looking professional, and use this term ('should look professional') if you get into any arguments with users.
This sort of approach should let you answer people's requests for colour while still maintaining a degree of professionalism (and self-respect). You can be seen to accomodate user requests without looking like an idiot.