Begonia soli-mutata

A gorgeous Brazilian species grown mainly for its deeply textured richly coloured foliage (it also has pretty white flowers) Not difficult as a house plant as long as not dry. Regular misting helps.
£8
Raphiocarpus petelotii Finale

A subtropical gesneriad from Vietnam. The soft fuzzy leaves are marked with black and silver and wine red underneath. The flowers are creamy, cornet shaped with darker markings within. Said to be almost hardy by some, it certainly needs cool humid shady conditions and is probably best in a terrarium.
£8
Drymonia chiribogana

A bushy gesneriad from Latin America with dark lustrous leaves and silver veins. The flowers are pale lilac. A plant for a terrarium or tropical greenhouse. It survives as a houseplant but really needs good humidity. Not at all difficult given the right conditions.
£8
Crassula streyi

A tender South African species with 2in wide broad glossy leaves – dark green above, slightly marbled in silver, and intense wine red under.

Like many plants with red leaf reverses, this is an adaptation to growing in shade, which makes this an excellent choice for a sunless windowsill and irregular watering – the ideal houseplant in many ways. The flowers are small and off white and produced in branching sprays in spring.
£6