More than 8 years after closing its US operations, Japanese cooling specialist Scythe is back with a brand new site, and a great news : their flagship Ninja 5 CPU cooler now officially supports passive cooling: "Massive heatsink and 6 sintered heatpipes provide top-tier performance and potential for fanless solution for completely silent PC." No mention of TDP limit, but the 1kg heat sink can probably handle a 65W CPU in an open-air setup.
Source: SCYTHE, Inc.