The commonly seen "blue hedgehogs" as well as some less well known clump formers. All for well drained soil in full sun.
The fescues are probably one of the most widely planted Ornamental Grasses in the UK thanks to the huge numbers sold as container plants alongside various evergreen shrubs and small conifers. Unfortunately where the shrubs and conifers are more than likely to vastly outgrow these containers the Fesctuca will almost certainly get squashed and die!
The key to growing Festuca, as with alomost any other plant, is to look at where they come from in the wild. The majority of fescues grow in poor soil with little nutrient and low rainfall, mostly in full sun, and mostly with little competition from surrounding other plants.
So, for most success with Festuca, plant them in conditions that closely mimic the habitat they have evolved for - poor, dry soil in full sun. As always, of course, there are some exceptions!