Waltzes sit in a quieter corner of the bluegrass and old-time repertoire — slower 3/4 tunes that contrast with the faster reels and breakdowns. Bill Monroe wrote bluegrass waltzes (“Kentucky Waltz” is the most famous vocal one); the instrumental side has fewer but enduring tunes that get pulled out late at jams when the energy comes down.
Each tune’s page on Picker’s Guide has chord charts, recordings, and notes on arrangements.