ShredDB is an experimental .shred library, I removed the audio so it's pretty useless. You can find the source .psarc files here.

Song	Artist	Play	Shred	Length	Album	Year	Tuning	Uploader	Updated	Delete
Kohaku no Kuchizuke Marika and Ibuki duet edition	Hinatabi Bitter Sweets			4:00	Home Sweet Home	2017	E Standard	mute	1970-01-01
Lakme. The Flower Duet	Leo Delibes			1:38	lak	1883	E Standard	mute	1970-01-01
Maldito Duende	Héroes del Silencio			4:18	The Platinum Collection	2006	E Standard	mute	1970-01-01
Overdue	Muse			2:28	Showbiz	1999	E Standard	mute	1970-01-01
Overdue	The Get Up Kids			3:02	On a wire	2002	E Standard	mute	1970-01-01
PIANO DUET	VAMPS			4:33	BEAST	2010	Drop D	mute	1970-01-01
Planet Dance (Duet)	FIRE BOMBER			4:20	Let's Fire!!	1995	E Standard	mute	1970-01-01
Shadow Duet	Dark Tranquillity			7:08	Skydancer	1993	C# Standard	mute	1970-01-01
Sleepless Due to the Night	UNDEAD CORPORATION			4:06	I'm Already Dead?	2011	Custom Tuning	mute	1970-01-01
Ten Duel Commandments / Meet Me Inside	Hamilton			3:15	Hamilton (Original Broadway Cast Recording)	2015	E Standard	mute	1970-01-01
The Duel	Dethklok			2:38	The Doomstar Requiem - A Klok Opera Soundtrack	2013	C Standard	mute	1970-01-01
The Duel	Rusty Cooley			3:54	Rusty Cooley	2003	Custom Tuning	mute	1970-01-01
The Duellists	Iron Maiden			6:08	Powerslave	1984	E Standard	mute	1970-01-01
Totsugeki Love Heart Duet	Fire Bomber			4:17	LET'S FIRE!!	1995	E Standard	mute	1970-01-01
Wicked Child Duet	Kinuyo Yamashita			1:59	Castlevania	1986	Drop D	mute	1970-01-01