The hole-free TO247/SC65/SOT429 is TO274. The TO264/SOT430 also has a hole-free version, but I've yet to run across a designator for it. TO220 and TO126 also had a number of hole-free versions in Europe and Asia (2-10T1A and SOT82/SOT194).
Semiconductor packages that have seriously addressed thermal interface issues generally either have the mounting 'screw' integrated into the body (ie stud), use multiple mounting holes that apply pressure to the mounting surface at equidistant points, or engage a clamping structure
- again usually with more than one clamp support position. These are more common in industrial RF or traction/inversion power devices.
You see the same principles applied in Japanese commercial plastic power parts like the M38, MT200 and HPAK/2-34H1A. All of these were ignored by 'western' industry, and continue to languish in limbo.
On the side of the ridiculous, multiple hermetic versions of the TO220 were developed for MIL and aerospace in the TO257 and TO265, which just shows how stupidity can be duplicated, in the process of quick and dirty design 'militarization' - though there already was a two-screw version in the TO254. Similar hijinks occurred with TO218 package sizes.
RL