I have one garden that is in total shade all day, and by that, I mean NO sun. Contrary to what the seed package says, I have grown nasturtiums in full shade with glorious success. I have also had great success with camelias, hydrangea, impatients, day lilies, hellebores, astilbe, and begonias - also in total shade. For late winter to early spring, hellebore is a long-blooming variety. Camelias lead the way in later winter as well, there are a few varieties that start blooming in December, one of which is Yuletide. The rest of those I mention are summer flowering plants. Two perennial plants I like are Brunneria, which does not have big blooms, but the foliage is stunning, and Ligularia. There are two varieties of Ligularia that I know of. Both have amazing foliage. One blooms in late summer, the other in late fall.
You might also consider some shrubs, assuming you have space, that have colorful foliage such as Mexican Orange.
