For mic I use the old Nokia's mic attachment and put my own IEMs to it. That way I have a mic and I can use my favourite IEM too.
What nokia mic? Well, the old N series had the earpiece in two pieces in which it could be detached midway. I use the bottom piece with the mic that came with nokia for my phones.
If not that there are not many third party earpieces I know of. Keep a lookout. This is all I know. Good luck