Humorous songs often use irregular rhythms and playful lyrics. Notable examples found in the Bulgarian Humor Folklore Songs compilation include:
on the arrangers (like Emil Kolev or Philip Koutev).
If you are looking for a or specific sheet music for these arrangements, I can help you find: Score excerpts for choral practice.
The request refers to a specific collection of Bulgarian folk music titled (Cheerful and Humorous Folk Songs and Dances).