Epimedium x rubrum (red barrenwort):
Green heart shaped leaves tinged with red around the edges in spring. Small red flowers with yellow undersides. To 30cm. Hardy
Euphorbia myrsinites (Spurge):
Sprawling stems of glaucous leaves and acid green flowers in spring. Prefers full sun and good drainage. Hardy. Up to 30cm.
Lathyrus vernus (Spring pea):
Two-tone purple and pink pea-like flowers in early spring. Thrives in shade, even quite dry shade. To 30cm. Hardy.