To be honest choosing what you put on your roof depends on a range of factors including personal preference, pitch of your roof, the surrounding area and nearby houses as well as your budget.
You can choose from a range of colours and materials for pitched roofs including:

Slates – which can be black, grey or green
Tiles – which can be red, brown, black or grey as well as lots of different shapes and sizes
For pitched roof some of the materials we use include: Redland, Marley, Wienerberger & Russell Roof Tiles
Red Clay Tiles Redland Barrell Tiles Grey Slate Green Slate
For a flat roof you can use a number of materials including:
Armourplan, Rhenafol FK, Triflex, Soprema & Alsan
We can then also put Sedum Grass roof on top. Or you can use walkway tiles to make your roof more accessible.
We can also use many of these on pitched roofs also
Soprema with standing seams Grass Roof