This page contains information regarding Star Trek: Picard, and thus may contain spoilers.
They were a remarkably pleasure-oriented people, who also found great pleasure in bringing pleasure to guests. As such, they were known for their legendary hospitality.
In fact, they were mostly interested in the new and different, quickly growing bored with any particular person or activity.
Stories were an important part of their culture. More than entertainment – they seemed to be a measuring-rod of values and beliefs. They believed stories to be an essential part of every person's being, and would not retell them without permission from those who told them to them.
The Sikarians were a technologically-advanced race, having produced unusual technologies like their atmospheric sensor, and the spatial trajector, which could instantaneously transport a person up to forty thousand light years.
In 2371, the USS Voyager attempted to purchase this technology, but was turned down. A secret exchange was made anyway, but the trajector matrix turned out to be incompatible with Federation technology, due to it emitting antineutrinos. (VOY: "Prime Factors")
The Borg had assimilated a number of Sikarians, and, sometime between 2366 and the 2380s, started incorporating spatial trajector technology sourced from them in their Borg cubes' queencells. (PIC: "The Impossible Box")