I have a shade garden under a maple tree and next to a garage, it gets total shade and is constatly moist. What can I grow in it that will give it color?
You should be able to find what grows in your zone by using the nice chart at the link below that shows
Common Name, Botanical Name, Height, Plant Characteristics and Notes, USDA Zones, Growing Requirements.
I prefer evergreens because I don't like dull brown in winter as well as a variety of plants especially if you can see it from the house; however a sweeping groundcover could be easy care & provide some color. Maybe there are some natives in your area that will thrive.
Shredding the maple leaves & returning them to the area along with a mix of grass clippings or used coffee grounds for nitrogen/greens will make the soil easier to dig holes for transplanting in spring.
Vinca minor is an evergreen that covers well in my climate as long as you remove the maple leaves that land on top of it in the fall.
Lily of the valley (Convallaria majalis) thrives in deep shade, but people comment that they wish they'd not planted it because they can't remove it when they want to grow something else.
Lamium loves moist shade, so would be interesting in during the growing season & there are several different leaf and flower colors.
Here is a link that might be useful: Plants and Flowers that are Able to Grow in Full Shade
Ajuga may also be an option. There are several varieties.
Wasn't clear from your post if you're looking for perennials or annuals. Your local garden center(s) should have a section of shade-loving perennial plants. Hopefully they have some that are not exotic invasives. Sounds like a great spot for a mixed Coleus garden, absolutely colorful, if you're interested in annuals.