It's all in my signature.
Discounting IEMs I currently own Aeon Flow Closed, Hifiman Edition X v2, Sennheiser HD600 and NAD Viso HP50
I know they are not Soundstage Kings like HD800/S though
It may not rival the HD800 (that's an awfully high bar), but IMO the HEX v2 has a striking soundstage...great width + all around the head. Certain transients, especially percussion, are very distinct in space w/this headphone.
I recall the Empyrean having very good soundstage, too--though I was so wowed by its design beauty & overall sonic profile that soundstage was not uppermost in my mind.
I tend to pay less attention to soundstage than tonality/timbre & dynamics. But whenever it's well above average, I reap the benefit.