The engineers over there have done some incredible things, first with the tack sharp APS-C 18-35mm f/1.8, and now with the new APS-C 50-100mm f/1.8. The new 50-100mm f/1.8 — which will come in Canon EF, Nikon F, and Sigma SA mounts — joins the rest of Sigma's high-performing Art lens lineup, and is listed at $1,100. In addition, they've announced another new APS-C lens for their mirrorless line, the 30mm F1.4 DC DN, which will be available in Sony E and MFT mounts, and is listed at $340. Lastly, the previously leaked E-Mount adapter, MC-11, has also been announced, and will cost $250. Unfortunately it seems that it will only work with Sigma lenses out of the gate.

All three of these will be available in the next month or two.

50-100mm f/1.8 DC HSM Art 

• Canon EF, Nikon F, and Sigma SA Mounts, Covers APS-C Sensors
• Features three FLD (F Low Dispersion) glass elements, one SLD (Special Low Dispersion) glass element, and one high-refractive index, high-dispersion glass element to minimize aberrations.
• Redesigned and enhanced, the new Hyper Sonic Motor is 30% slimmer and provides fast and accurate AF.
• Highly durable polycarbonate diaphragm made with fluorine; blades feature carbon feather film offering exceptionally smooth operation even during continuous shooting.
• Inner focusing and zoom design offer versatile shooting options
• Tripod socket for stable, comfortable operation
• Features 21 elements / 15 groups,
• Minimum Aperture: F16
• 82mm filter thread
• Minimum Focus Distance: 37.4in
• Dimensions: 3.7x6.7
• Weight: 52.6oz
• Availability: April 2016
• Price: $1,100

30mm f/1.4 DC DN

• Sony E-Mount and Micro Four Thirds Mount, Covers Up to APS-C Sensors 
• Represents first affordable F1.4 performance lens for the mirrorless market
• Sigma engineered quality within a sleek compact design
• Fast, smooth AF stepping motor designed to support video
• Features one aspherical element and one double-sided aspherical element producing imaging quality comparable to the Art line.
• Features 9 elements / 7 groups
• Minimum Aperture: F16
• 52mm filter thread
• Minimum Focus Distance: 11.8in
• Dimensions: 2.6x2.9in.
• Weight: 9.3oz
• Availability: March 2016
• Price: $340

MC-11 Lens Converter

The MC-11 lens converter is designed for Sony E-Mount cameras, and though it seems like it's only made to work with Sigma branded lenses, theoretically there is nothing stopping them from developing the tech to work with other brands in the future. Right now the adapter is made to work with Sigma SA and Canon EF mounts, adapted to E-Mount, runs for $250, and will be available at the beginning of April. Here's more from Sigma on the lens adapter:

The Sigma MC-11’s sleek LED display lets Sony users know if the attached Sigma lens is compatible and whether or not the MC-11 needs to be updated for that specific lens. Its internal control data system keeps detailed information on each compatible Sigma lens, automatically optimizing performance of AF drive, aperture control and other critical lens functions. The MC-11’s internal control data system also maintains continuity with key camera functions that control brightness and correct transverse chromatic aberration, distortion, and more. The complete compatibility with both Sigma lens OS and Sony in-camera OS ensures correction of camera shake and other stability issues and when used with in-camera stabilization, MC-11 allows angle shake correction in the lens. The integrated flocking helps prevent internal reflections and reduction in lens performance. In addition, the MC-11 retains important EXIF data ensuring users can analyze every detail of their lens setting.

The Sigma MC-11 converter can be updated with the latest compatible lens information from a workstation or laptop using the Sigma Optimization Pro software and Sigma USB Dock (sold separately).

And here's the compatibility list:

It should also be mentioned that Sigma offers a lens conversion service, and will convert one Sigma lens mount to another:

Sigma will convert the current mount of your Sigma Global Vision lens to another of your choice. Sigma lenses currently from the Contemporary, Art or Sports line, in Sigma, Canon, Nikon, Sony, Pentax mounts can be converted to Sigma, Canon, Nikon, Sony or Pentax*. Mirorrless lenses can be converted to Micro Four Thirds and Sony-E Mount. They cannot be converted to either an APS-C or a Full Frame format.

For more info, be sure to check out the links below.

50-100mm f/1.8 

30mm F1.4 DC DN 

MC-11 - Lens Adapter