Blackout fabrics are available on every single type of shade. Although it's a little impractical on some of them, it's still available. The reason a lot of blackout fabrics make little to no sense on a lot of shades is the dreaded light gap. The size of the gap from the edge of the window to the blind has got to be as small as possible or it really defeats the blackout purpose. For example, the roller shade is an exellent option in most rooms but it has a gap of 1/2 to full inch, since no light comes through the fabric, the amount of light that pours in from the edges is extremley noticable and frankly unacceptable.
There are two shades that are unquestionably the best blackout options. The Honeycomb shade and the Solera Roman shade. They have the smallest light gaps and also have the most practical top down bottom up controls. They are also the most energy efficient shades we have.
Bedrooms are the most obvious place for blackout fabrics but we also use them for rooms that have serious heat issues. Homes that have a western facing waterfront view have the worst heat issues because they get whacked from the sky and the glare off the water. That 5 o'clock sun can make a lot of rooms intolerable and puts a lot of stress on your air conditioner. Although the blackout fabrics aren't as pretty as light filtering fabrics, making your 96 degree sunroom 84 degrees has a beauty all its own.