You read that correctly: f/1. Fujifilm is planning a lens that will be the first of its kind.
The news came today when Fujifilm released its latest lens roadmap (side note: I love that the company tells us exactly what lenses they're developing and roughly when to expect them). The news coincides with the announcement of the XF 8-16mm f/2.8 R LM WR and XF 200mm f/2 OIS WR lenses and also includes the addition of two other new lenses to the roadmap: the XF 16mm f/2.8 R WR compact prime and the XF 16-80mm f/4 R OIS WR. Fujifilm plans to release the 33mm f/1 likely in 2020.
Nonscientific, consumer lenses of this sort aren't completely unheard of. In 1989, Canon introduced the EF 50mm f/1.0L. Though an amazing feat, image quality at wide apertures was lacking and autofocus was predictably slow, and it was eventually discontinued for the friendlier 50mm f/1.2L, though elements of its design ended up in the 85mm f/1.2L. You can also buy mirrorless and rangefinder lenses with maximum apertures as low as f/0.85 (though f/0.95 is more common), but these are all manual focus. As such, Fujifilm's upcoming 33mm f/1 lens would be the world's first autofocus mirrorless lens of such an aperture and as far I can tell, the first consumer-level f/1 lens with autofocus in about three decades (and likely only the second in history).
For reference, f/1 is a little over half a stop faster than f/1.2 and a full stop faster that f/1.4. While Canon has shown such a lens is not unprecedented, I'm very curious to see what 30 years of advances in optics and autofocus technology will do; Fujifilm's version could end up being a prized item among portraitists and events shooters.