There are several floating bases in Uranus’ atmosphere to control the robotic mining of helium-3. Due to the low escape velocity, the relative thin rings of debris and optimal gravity situation at 1 bar in the atmosphere, Uranus is a perfect site for gas mining.
There have been several unmanned missions to explore whether Neptune’s icy moon Triton is interesting for exploitation. Triton consists largely of nitrogen and water ice, covering a subterranean ocean. However, because of the geological activity on the surface of Triton, profitable exploitation is unlikely at this stage.
Neptune itself has also been considered as a site for He-3 mining, however, while having less erratic atmospheric conditions than Jupiter and Saturn, Uranus seems to be a more profitable location due to an even calmer atmosphere and a smaller distance from the inhabited areas of the solar system.