答案：不会。
https://markrosewater.tumblr.com/post/671924368266444800/since-we-have-modern-horizons-as-a-product-for
Since we have Modern horizons as a product for Modern, do you think we one day will have a Legacy horizon’s with card just for the eternal formats but with the possibility of playing sealed?
We make numerous products aimed at Commander and those have lots of new cards for eternal formats. Making cards specifically for Legacy has two main problems:
1) A tiny, tiny percentage of the playerbase plays Legacy. In some parts of the word, it’s not even viable as a format due to card availability issues.
2) The power level of Legacy, as a constructed format at least, is so high, it’s tough to make cards for the format without causing all sorts of issues.