My Onc. Twinkle Pink Profusion, smells like cheap chocolate. It's been undemanding, but definitely not as strong as the Onc. Sharry Babies I've smelled at various greenhouses.
I'll have to keep an eye out for some of the hybrids listed above.
The species Onc. fuscatum has great fragrance. Look up the photos and you'll recognize it in its progeny. It's fairly large. Onc. ornithorhynchium and sotoanum have a baby powder fragrance and are small.
__________________ May the bridges I've burned light my way.
I have an Onc Heaven Scent 'Sweet Baby' blooming for past couple of weeks. One spike, about 3-1/2 feet long. Recently divided this past spring. Brought it from grow space into dining room. It fills the room with chocolate. I'm starting to wonder if it was a mistake putting it so close to kitchen and pantry. My cravings for chocolate have really intensified since the move.
I like it a lot more than any of the Sharry Babies or Twinkles I've owned. Have a Ons. Catatante 'Orange Kiss' and a Ons. Catatante 'Pacific Sunspots'. They have a more vigorous growth habit than the Heaven Scent, but don't spike any better than it. Neither of them has much of a scent to speak of unless you're within sniffing range.
__________________ Caveat: Everything suggested is based on my environment and culture. Please adjust accordingly.