I like some post-hardcore but I can't really recall anything. As far as metalcore goes, I kinda dislike anything that isn't Converge or HORSE the band. Sounds way too generic to me. I just don't really like the "intro/verse/chorus with clean vocals/breakdown/verse/chorus again/chorus with harsh vocals/breakdown" formula.
Some real screamo (or "skramz" if I may) has got some post-hardcore elements, but it may just be hardcore elements since they're both hardcore subgenres.
well their not at or near the very root of metal, their subgenres of earlier metal themes Metalcore is a fusion genre of hardcore punk and extreme metal Post Hardcore comes from hardcore punk which comes from punk rock Electronicore is both but with electronic music [DnB, Dubstep, etc]
its metalcore or post hardcore but with synth, keyboards, and electronic music added -Hands Like Houses is a good electronicore band, try their songs "A clown and his pipe","Antartica" or "Lion skin" if you want