My personal TOP 5 IEM's for metal (all relevant genres including death/black/doom/thrash)
1. Aur Audio Aures - The kings due to their technical ability, stage, bass speed. heft and resolution and most of all, the crystalline mids
2. TRN ST7 - The newest stunning budget brawlers for metal! Resolution, bass, timbre, detail retrieval, and stage set the scene for amazingly rendered madness!
3. CCA Trio - If the Trio had just a bit more thickness in the mids, and a touch more resolution, they'd be ahead of the ST7, but they lack where the ST7 doesn't, but still stunningly great for metal lovers for all they do right, including the detail retrieval and that special sauce stage and imaging.
4. Simgot EA500LM - Pretty close to the Trio, but a point deducted for that nozzle filter imbalance (gold filter reigns in the treble too much, and the silver/red ring provides just a touch too much treble at times, causing some grain and sibilance), but still killer for metal of all subgenres. A classy musical listen.
5. Zero Audio Tenore/Simgot EW200 - Tied. Both provide great mids, extended treble and resolution needed to excel with metal, but both lack bass heft, and the mid bass is soft, so lacking the total package that makes for peerless listening to all subgenres. Still, on a budget, and on the go, they will step in just fine, just not great.