Sony recently has filed two super telephoto prime lens patents along with Sony FE 400mm f/2.8 GM OSS Lens (B&H Photo Video). This two lenses are Sony FE 500mm f/4 GM lens and Sony FE 600mm f/4 GM lens. The announcement of these two lenses could be in 2019 to 2020.
According to recently rumors, Rokinon is going to announce a new Samyang AF 24mm f/2.8 FE lens next several days. This is new lens is available for Sony FE mount. According to rumors, this lens will be a pancake lens, same size as Samyang AF 35mm f/2.8 FE lens.
According to Nokishita Camera, the new Sigma 105mm f/1.4 DG HSM Art Lens for Sony E-mount will be available for pre-order on May 25th, 2018. The rumored US price is below $2,000. You can check price and pre-order options at B&H Photo Video.