Completely reusable rocket that can carry 100 tons into low Earth orbit, refuel, and then continue on to places like Mars. Launches are estimated to cost SpaceX about $2M, compared to the SLS $1B (estimated, similar lift capability) and space shuttle $1B (27 tons). The engines are real, test vehicles are flying (another test launch is likely to happen in the next week or two). Follow the SpaceX subreddit for progress updates
2. Commonwealth Fusion Systems - http://cfs.energy
Lots of reactors have struggled with scale and plasma instability. CFS has adopted a design using new REBCO high temperature superconductor magnets that are stronger and smaller, which can be used to build smaller reactors and better stabilize the plasma. They are building a prototype called SPARC, expected to produce net energy gain by 2025.