Yes, it's absolutely possible to tune your guitar to sharp and flat chords while still keeping an open tuning. You can tune your guitar to any chord that you want, whether that's minor chords, major chords or dominant seventh. While in some contexts these tunings will work perfectly, such as blues and rock music, if you want to play pop or more classical pieces then these slide guitar tuning options won't work. This is why we focus mainly on open tunings in our article, because they are the most versatile and the ones that are used most often by popular and current guitarists.