Hi Sean thanks for posting in the Lucidchart Community! If you are referring to icons as part of Lucidchart's conditional formatting feature there are a variety of icons offered as shown in this screenshot. 

For more information on how to achieve this please take a look at the Conditional Formatting article in our Help Center.

If are referring to SVGs that are imported into Lucidchart as custom shapes it is currently possible to adjust the color of imported custom shapes. However which color of the custom shape is linked to the "fill color" depends on the formatting of the original SVG file. This also depends on the complexity of the shape.

If you would like to submit a feature request you can do so through our Product Feedback section. Ideas submitted are passed on to the product development team for their consideration.

Hope this helps!