Most conservatively, there are tokamaks that use more modern superconductors, able to support much stronger magnetic fields. Tokamak output scales with the four

Most conservatively, there are tokamaks that use more modern superconductors, able to support much stronger magnetic fields. Tokamak output scales with the fourth power of the magnetic field, so that allows the same output as ITER from a much smaller, cheaper reactor. The MIT spinoff CFS is doing this, along with Tokamak Energy in the UK. CFS is shooting for a net power attempt in 2025. There are also various alternative designs, like Zap Energy's z-pinch, General Fusion's magnetized target fusion, and Helion's field-reversed configuration. Helion is attempting hybrid D-D/D-He3 fusion, the other two are D-T.