For Interplanting/Accents up to 3 feet in height:
Amazon Lily (Eucharis amazonica)

Bromeliads (Aechmea spp., Neoregelia spp.)

Clivia Lily (Clivia miniata)

Cycads (Zamia maritima and Zamia pumila)

Dwarf Sansevieria (Sansevieria trifasciata 'Twist', 'Gold Hahnii')

Fancy Frill Fern (Nephrolepsis falcata furcans 'Fancy Frill')

Fishtail Fern (Nephrolepsis falcata furcans)

Mondo Grass (Ophiopogon japonicus and cvs. 'Nanus', 'Super Dwarf')

Sword Ferns (Nephrolepsis exaltata 'Erecta', 'Dallas', 'Compacta')

Wart Fern (Microsorum scolopendria)
To create easy shade (6-10 feet) for begonia plantings underneath:
Angel Trumpets (Brugmansia spp.)

Bananas (Musa spp. and Ensete spp.)

Firebushes (Hamelia cuprea, H. patens, H. patens 'Glabra')

Gardenia (Gardenia augusta 'Miami Supreme')

Golden Dewdrop (Duranta erecta)

Lavendar Star Flower (Grewia occidentalis)

Peregrina (Jatropha integerrima, J. integerrima 'Rosea')

Tropical Lilac (Cornutia grandiflora)

Yesterday-Today-Tomorrow (Brunfelsia grandiflora, B. australis)