Acorus 'Minimus Aureus' forms a slowly-spreading groundcover of finely-textured, linear, golden foliage.
Andropogon 'Blackhawks' is a big, bold grass with deep purple leaf tips and burgundy red inflorescences in mid summer all becoming purple black in fall.
Festuca 'Beyond Blue' is one of the bluest of all fescues and for that matter all grasses!
'All Gold' is a full on golden grass for the shade garden. Hakonechloa are the best grasses for the shade.
Panicum virgatum 'Heavy Metal' is a dramatic switch grass forming vertical pillars of metallic blue foliage.