Some annuals are great houseplants, some can be saved over winter

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The ones that can survive with less than full sun are the best candidates for appropriating to the great indoors, or trying to save over winter. When sold as annuals, these are usually very inexpensive, and sometimes found in 4- or 6-packs for just a few dollars.

Worth buying AS houseplants: These are some I've kept going for years at a time.

- Any Begonia. (List = endless...!) Wax & rhizomatous (Beefsteak, Rex) bloom inside if they can be by a sunny window for winter.

- Spikes. These are Dracaenas. Over time, they will keep going up, forming a trunk.
Dragon Tree (Dracaena reflexa var. angustifolia)
Cabbage Tree (Cordyline australis)
Mountain Cabbage Tree (Cordyline indivisa)

- Any Plectranthus, most are not unhappy inside, though 'Mona Lavender' is so often reported as fussy. Going into winter with low expectations is probably best.
Variegated Cuban Oregano (Coleus amboinicus 'Variegatus')
Spur Flower (Plectranthus Mona Lavender)
Gold-Edged Plectranthus (Plectranthus forsteri 'Aureus Variegatus')
Swedish Ivy (Plectranthus verticillatus)

- Kalanchoe blossfeldiana (flaming Katy) https://garden.org/plants/sear...

- Alternanthera ficoidea and dentata.
https://garden.org/plants/sear...
https://garden.org/plants/sear...

- Streptocarpella https://garden.org/plants/sear...

Maybe not for inside all year (depending on your window situation) but worth trying to save if you want to. I've successfully saved these over winter multiple times.

- Pelargonium (zonal Geranium.)
Pelargoniums (Pelargonium)
Storksbill (Pelargonium 'Citronella')

- Hypoestes phyllostachya (polka dot plant), comes in several colors of polka dots. Older stems die off over winter and new ones grow from the soil level. I think many people give up at this stage, but if given a chance and it does stay alive, it will be bigger and better than the previous year.
https://garden.org/plants/sear...

- Persian shield (Strobilanthes dyerianus.) Probably going to be ugly for winter, but definitely save-able.
Persian Shield (Strobilanthes auriculatus var. dyeriana)

- Coleus! Comes in a nearly limitless selection of leaf colors and patterns. Going to the store to find a particular one will be reliably disappointing. There are too many, and few are actually in commerce in any given year, compared to the number of actual cultivars.
https://garden.org/plants/sear...

- Also this popular cousin of Coleus, Perilla 'Magilla' Beefsteak Plant (Perilla 'Magilla')

- Portulaca umbraticola (ornamental purslane.) Wingpod Purslane (Portulaca umbraticola)

- Purple heart Purple Heart (Tradescantia pallida)

- Mezoo / sunrose (Mesembryanthemum cordifolium.) I usually see variegated.
Baby Sunrose (Mesembryanthemum cordifolium 'Variegata')

- Dahlia Dahlias (Dahlia)

- Gerbera daisies https://garden.org/plants/sear...

- Impatiens, mixed results but enough success to try repeating.
https://garden.org/plants/sear...
New Guinea Impatiens (Impatiens hawkeri)

- Mandevilla https://garden.org/plants/sear...

- Sweet potato vines (Ipomoea batatas) https://garden.org/plants/sear...

- Euphorbia 'Diamond Frost' Euphorbia (Euphorbia hypericifolia Diamond Frost®)

- Various ferns.