Gifts to go with bouquets in Singapore: what stays in the flat
More than three quarters of Singaporeans live in HDB flats, so most gifts to go with bouquets in Singapore end up in one of those flats, where a diffuser or candle stays for weeks after the roses are gone. A gift is chosen by what it needs to do. It can join the party on the day, stay in the flat for weeks after the roses are gone, or carry a few words the sender didn't say out loud.
A red foil heart, marshmallow stems or a performer for the party
Red is the colour of celebration, weddings and luck in the Chinese tradition most Singaporeans follow, so a Heart Foil Balloon suits a happy occasion rather than a sad one. Nothing red is brought to a funeral.
Latex holds its helium for about half a day, while foil keeps a balloon aloft for several days. Daytime temperatures sit at 31–33 °C all year, so latex loses its helium faster here (more on flowers in the heat). A latex balloon suits the day itself, while a foil one, such as a Star Foil Balloon, can be ordered ahead without worry.
A gift doesn't have to be a flower at all. Marshmallow bouquets trade stems for sweets, a treat rather than flowers, while a performer booked with the bouquet turns the handover itself into part of the occasion rather than a delivery that comes and goes.

A rose cut for a bouquet lasts about a week in water, while reed diffusers run for weeks or months, depending on the bottle size and the room they scent. The reeds themselves want turning every few days, a small routine rather than a chore.
That's what makes reed diffusers and candles and vases a different kind of gift to add: one meant for the flat itself, not for the flowers passing through it. A vase, in particular, is a gift for whatever stems come next, not for this one bouquet alone.
A card signed, left blank, or set among the stems as a topper
A card with a written message costs nothing extra. It can be signed or left anonymous, and the sender's contacts never reach the recipient: the courier hands over only what was asked for, nothing more. Anyone who would rather pick a line than write one can turn to printed greeting cards, while a topper is set among the stems instead of tucked into an envelope.
Sending from abroad works the same way as any bouquet ordered here.

Balloons, sweets or a vase go into the cart with the bouquet, so gifts with flower delivery in Singapore arrive as one order. A florist photographs the finished bouquet before the courier sets out, delivery time shows on the bouquet's page, and the terms are on delivery terms. For a party, entertainers are worth a look; for something that outlasts the week, start with the diffusers.