Boost requires attribution in the source form (you can't remove the copyright notice from the source repo when redistributing). The second paragraph of the license:
> The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
works are solely in the form of machine-executable object code generated by
a source language processor.
It's similar to MIT or Apache-2.0 in that respect. As for Unlicensed and WTFPL, sure they're both effectively the same as CC0 (though I would personally be cautious about removing copyright notices from a WTFPL codebase).
> The copyright notices in the Software and this entire statement, including the above license grant, this restriction and the following disclaimer, must be included in all copies of the Software, in whole or in part, and all derivative works of the Software, unless such copies or derivative works are solely in the form of machine-executable object code generated by a source language processor.
It's similar to MIT or Apache-2.0 in that respect. As for Unlicensed and WTFPL, sure they're both effectively the same as CC0 (though I would personally be cautious about removing copyright notices from a WTFPL codebase).