I have same condition and my shade garden consists of ferns, banana trees, elephant ears, iris, canna lillies (don't know proper name). My garden gets about 2 to three hours of partial sun and is rather soggy on one end. I also allow some kind of wild cane to grow which makes a pretty white flower. If I remember correctly, I believe bamboo grows well in wet conditions. The cane and bamboo cane take over real quick though.

both itea (virginia sweetspire) and clethra grow well in wet shade

But clethra needs sun.

If cinnamon fern and royal fern are hardy for you (I only worry about the heat in your area), those plants can tolerant quite wet conditions and they can get huge. I visited someone with these growing wild in a soggy area and I thought I'd stumbled back into the jurassic period!

I'm growing a beautiful clethera in mostly shade; it seems significantly more affected by the moisture than the sun. Ligularia will do nicely and probably hostas, provided they stay moist when your heat kicks up. I'd give them a try if it were me, there are Soooo many varieties. Chameleon or houttentoyia would survive and has some awesome color for the shade but might become invasive in your zone, I'm not certain. It's a serious runner here so maybe your heat would keep it in check. Remember that anything that fills in the space quickly could be a serious nuisance in a few years, so maybe better to live with a somewhat sparse looking area for a year or two instead of having to break your back thinning it 3 years from now forevermore. (That's from my "Note-to-self" list for sure!)

why dont you try petasites ~~~~ japanese butterbur. the giant kind get 6 ft tall with 3 ft wide round leaves and spreads easily. it will take a couple of years to establish, mine went from a 3 in pot to a 10 ft patch in 4 years. in moisture it will really spread, but roots spread laterally right below the surface, so are easily removed, or easier yet, mowed down. i can send you a link to my online pics if you're interested susgarden

Watch out for the chameleon and the bamboo. Both can be very invasive if given conditions they like. I do well with clethra, Red Twig Dogwood, and leucothoe.