It seems like being able to reproduce from a single detached leaf would be so convenient that you'd think every plant would have figured out how to do it, but it's actually a pretty rare quality, limited mostly to succulents, most gesneriads,1 and a few random others.
One of the big problems when starting regular stem cuttings2 of a plant is that until there are roots to take up water from the soil (or rooting medium), the cutting will transpire3 a lot of water through the leaves. For some plants, like Ficus elastica, it's actually recommended that you either remove most of the leaves before trying to root the cutting, or that you cut the leaves in half, so that they'll be able to hang on to more of their moisture instead of transpiring it away.
My theory is that plants that can propagate from single leaves have this same problem, but even more so: they don't even have any stem in which to store water, so they run an even bigger risk of breathing all their water away. Therefore, the plants which are already adapted to hang on to their water, i.e., succulents, would be the ones that would have the easiest time getting by while they wait for roots to start. It's just a theory, and it doesn't account for some of the plants on the list so it's obviously not the entire story, but it seems more or less logical to me, anyway.
As ever, I'm open to additional suggestions, if the reader thinks of something I've left out.
Episcia cvv? (flame violet) -- ought to in theory, though I've never seen anybody say they did it, so I'm not sure about this.
Haemanthus albiflos (shaving brush plant, elephant's tongue)
some Hoya spp. -- by rumor only. Species like H. kerrii (sweetheart hoya) will root on individual leaves fairly easily, but I'm unclear about whether they'll produce new vines from a single leaf, or if so how long that might take.
Kalanchoe blossfeldiana (flaming Katy, florist's kalanchoe)
Kalanchoe bracteata 'Silver Teaspoons' -- see post.
Kalanchoe tomentosa (panda plant)
probably most Kalanchoe spp., really
Nematanthus cvv.? -- like Episcia: it's a gesneriad, so it ought to, but that doesn't mean it actually does. (Nematanthus leaves tend to be small, so they may not be able to store enough water for this to work.)
Peperomia argyreia (watermelon peperomia)
Peperomia scandens (false philodendron)
most Pinguicula spp. (butterworts)
Sansevieria trifasciata cvv. -- though some variegated varieties won't come true from leaves and can only be propagated via runners.
Sedum burrito, Sedum rubrotinctum, most other Sedum spp.
Streptocarpus cvv. -- usually propagated by leaf section cuttings, as for Begonia. New plants can only arise from the leaf midribs, so usually leaves are cut into chevron-shaped pieces and planted in vermiculite or a similar medium.
1 Gesneriad = one of the plants in the family Gesneriaceae. African violets (Saintpaulia) are the most commonly-encountered gesneriads, but Streptocarpus (cape primrose), Aeschynanthus (lipstick plant, goldfish plant), Nematanthus (guppy plant, goldfish plant), and Columnea are also sold pretty routinely.
2 Stem cutting = most commonly a short (3-4 inch / 8-10 cm) piece of stem, plus leaves or side branches or whatever, rooted in soil, water, or a sterile medium like vermiculite or perlite, for propagation. The most common method of do-it-yourself plant propagation.
3 Transpiration = the loss of water through pores on the leaf surface. Most plants have these pores (called stomata) open during the day, where they can take in carbon dioxide and release oxygen. Along with oxygen, a certain amount of water is also lost, depending on the temperature, humidity, wind, and so forth. In a plant which is growing normally, the roots replace the water lost to transpiration by taking new water up from the soil.
4 Petiole = the "stem" connecting a leaf to the plant's main stalk.
5 It's not a particularly good sign, but it doesn't mean that everything's lost, either.