Maintaining color consistency in your icons is vital for a harmonious user experience. Typically, a single, standout color for important or active icons works well, alongside a different uniform color for the rest. This makes it easier for users to spot key functionalities without feeling overwhelmed. For example, an active icon in the bottom navigation bar might be in your brand's main color, while inactive icons could be a muted version of that same color or a neutral shade like dark gray.

The key is to choose colors that not only are consistent but also fit seamlessly within your interface's broader design palette. Inconsistencies in color can lead to user confusion, so once you've picked your palette, stick with it to ensure a cohesive and user-friendly experience.