A few examples of how it sounds when you use alternative guitar tunings like
Open G, DADGAD (Open Dsus4), Open G6, Open C, Open E, DADF#Be
Dropped D songs are NOT included, you will find them on another list

Akihiro Tanaka - Flower (CGDGBD)

Beatbox Guitar - Little Song Of First Desire (BADGBE)

Boyce Avenue - Demons (CGCFBC "almost like DADGAD")

Boyce Avenue - The Climb (DbAbDbAbDbDb)

Dougie MacLean - Caledonia (Open C - CGCGCe)

Dylan LeBlanc - Changing Of The Seasons (DADF#BE)

Galileo Galilei - Aoi Shiori fingerstyle (Open Dsus4 - DADGAD)

Gianni Palazzo - O Sole Mio (Open G6 - DGDGBE)

Infinite - Destiny fingerstyle (FAEGBE)

Jensen Trani - Hallelujah (Open E - EBEAbBe)

Jim "Kimo" West - Imagine (Open G - DGDGBD)

John 5 - The Castle (Open Dsus4 - DADGAD)

José Gonzalez - Heartbeats (DADF#BE)

Jung Yong Hwa - Banmal Song fingerstyle (Open G - DGDGBD)

Led Kaapana - Salomila (Open G - DGDGBD)

Loreena McKennitt - Skellig fingerstyle (Open Dsus4 - DADGAD)

Michael Chapdelaine - And I Love Her (CADGBE)

Part of Your World fingerstyle (Open Dsus4 - DADGAD)

Phil Cook - Frazee (Open D - DADF#AD)

Somber Guitar - Morning Sun (Open G - DGDGBD)

Stuart McCallum - Saltburn (Open Dsus4 - DADGAD)

Rodrigo Rodriguez - The Prayer (Open G6 - DGDGBE)