The answer to this question largely depends on the specific festival you are attending. However, there are certain types of music that are commonly found at festivals. For example, many festivals feature a mix of live music and DJs playing electronic dance music (EDM). Other popular genres of music at festivals include rock, hip hop, and pop.
Of course, the type of music you can expect to hear at a festival also depends on the time of day. For instance, most festivals have a main stage where the biggest acts play during the daytime. As the night goes on, smaller stages or tents typically feature DJ sets or more intimate live performances.
Ultimately, the best way to figure out what kind of music will be played at a particular festival is to check out the lineup in advance. This way, you can see which artists are scheduled to perform and get an idea of what genres will be represented.