Here is a long list of common and less common guitar tunings with free tuners. The guitar’s tuning options are limitless, so this is by no means exhaustive!
Standard Tuning
Guitar Tuner from GTDB gtdb.org
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Standard Tuning -2 (D Tuning)
Guitar Tuner from GTDB gtdb.org
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Standard Tuning -3 (C#/Db)
This tuning does not exists in the database
Standard Tuning -4 (C Tuning)
This tuning does not exists in the database
Standard Tuning +1 (F Tuning)
This tuning does not exists in the database
Drop C
Guitar Tuner from GTDB gtdb.org
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Drop D
Guitar Tuner from GTDB gtdb.org
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Double Drop D
Guitar Tuner from GTDB gtdb.org
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DADGAD (Dsus4)
Guitar Tuner from GTDB gtdb.org
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DADDAD
Guitar Tuner from GTDB gtdb.org
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Open A
This tuning does not exists in the database
Open C
Guitar Tuner from GTDB gtdb.org
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Open D
This tuning does not exists in the database
Open E
This tuning does not exists in the database
Open G
Guitar Tuner from GTDB gtdb.org
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Cross-Note D
Guitar Tuner from GTDB gtdb.org
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Cross-Note E
Guitar Tuner from GTDB gtdb.org
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Cross-Note G
This tuning does not exists in the database
Asus4
Guitar Tuner from GTDB gtdb.org
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C6
Guitar Tuner from GTDB gtdb.org
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Low C
Guitar Tuner from GTDB gtdb.org
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Dsus2
Guitar Tuner from GTDB gtdb.org
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Dsus4
Guitar Tuner from GTDB gtdb.org
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Gsus2
Guitar Tuner from GTDB gtdb.org
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Gsus4
Guitar Tuner from GTDB gtdb.org
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Low Major 3rds
This tuning does not exists in the database
All 4ths
Guitar Tuner from GTDB gtdb.org
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Augmented 4ths
This tuning does not exists in the database
All 5ths (“Mandoguitar”)
Guitar Tuner from GTDB gtdb.org
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“Iris” Tuning
Guitar Tuner from GTDB gtdb.org
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