Fragrance is a real bonus with indoor plants and some of the following have very powerful scents. The amount of fragrance these plants produce is usually related to temperature, with scent being stronger in warm rooms. In the case of pelargonium and plectranthus, it is the foliage rather than the flowers that smell, and they release their aroma when the leaves are handled.
Cyclamen persicum (some cvs.)
Echinopsis eyriesii
Exacum
Gardenia
Heliotropium
Hoya
Hyacinthus
Jasminum
Miltoniopsis
Narcissus papyraceus
Pelargonium (scented leaves)
Plectranthus (scented leaves)