For Mac, I've also used Falcon and Quiver. I know Quiver has an iOS app, and I think both save as just .md files so you can sync across apps with Dropbox or your cloud offering of choice.
Honestly, though, I'm out of good recommendations anymore for an all in one Markdown editor, so I just use a private Github/Gitlab repo and use the web editor since that lets you preview the .md output.
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