The lotus. Easy from seed and grows happily in the greenhouse. Never quite as happy outdoors but well worth experimenting.
Semi hardy evergreen shrub with pink to red flowers. Blends well with more arid plantings. Easy from seed.
Nice flowers shame about the plant. Not worth it if space is of a premium.
Plenty of flowers and taller varieties have a pleasant evening fragrance. It does not blend all that well with the tropical border as it fades too soon looking scruffy.
Water lilies can't help looking tropical. Every pond should have one.