Yeah, that sounds amazing, especially for a tiny indoor garden. Try mint for a bright green, borage for a subtle lavender, nasturtiums for orange and red, and a few dandelions for yellow. Those plants have pigments that are pretty easy to extract and they grow well in small pots. Keep a little spreadsheet of your yields—data on how many drops you get per plant is super useful for scaling. Just remember to keep the soil slightly acidic; my spreadsheets show that pH 6.5 is best for most of these.