The "IIDX" specification usually means the notes fall on the standard 7-key + turntable layout, with support for Long Notes (held notes) and Charge Notes (which require specific timing to release).
A: Skwid Inc. 25 or BOFXV: The Last Dance often feature "Kaiden" level charts (BMS's term for beyond human). Beatmania Iidx Bms Packs