open g dgdgbd,[gdgbd is a 5 string banjo tuning]is great for playing tunes,in a bumditty 5 string banjo style,I find playing melody with the thumb and doing the dit with index finger,and the ty with the index finger[up]similiar to carter family scratch ,gives the same rhythym aspete seegers bum ditty.
then one can start experimening with banjo tunings,dgdgcd etc etc.
incidentally dadf#ad is very similiar to dgdgbd,if you are playing tunes,a lot of the patterns , are just one string lower.
I find i use dgdgbd,more than daf#ad because I liking singing in a,capo on second fret,likewise dadgbd,A is quite good in standard tuning,but of course it sounds quite different.
so I am using drop d ,double drop d,spanish dgdgbd and dgdgcd as well as standard.
DGCGCD is one I intend to explore pretty soon[a variation on double c banjo tuning]