Intergenic regions may contain a number of functional DNA sequences such as  promoters and regulatory elements, enhancers, spacers, and (in eukaryotes)  centromeres. They may also contain  origins of replication,  scaffold attachment regions, and  transposons and viruses.
Non-functional DNA elements such as  pseudogenes and  repetitive DNA, both of which are types of  junk DNA, can also be found in intergenic regions—although they may also be located within genes in introns. It is possible that these regions contain as of yet unidentified functional elements, such as non-coding genes or regulatory sequences. This indeed occurs occasionally, but the amount of functional DNA discovered usually constitute only a tiny fraction of the overall amount of intergenic or intronic DNA.