To answer this one we will have to refine a few things. I think the question you mean to ask is "Were the vikings the only ones raiding."

Second, what is raiding? Raiding has been part of warfare for millenia as a way of disrupting the enemy, but when we talk about viking raids we usually mean pillaging and looting i.e. an army using force to steal material wealth and retreat before their enemy has the chance to organize a proper resistance.

The question needs to be further focused to a time and place. If we are asking whether the vikings were the only ones pillaging the Anglo-Saxon Kingdoms in the 9th and 10th century then we can safely say yes, basically. (I graduated with a minor in history and have continued studying it as a hobby, so please feel free to correct me if I'm wrong here.)

However, if we expand our scope a little, we will find that the Vikings were not the only group waging a pillaging style war against kingdoms in Western Europe from 600-1066 AD. (I'm using rough numbers for those years.) At the turn of the tenth century, East Francia, the ancestor to modern Germany, faced threats from the Magyars, who fought and pillaged their way across modern-day western Europe, sacking towns in West and East Francia as well as Italy and Burgundy.

Like Anglo-Saxon England and the Vikings, East Francia was ill-prepared to battle the Magyars because of their rapid appearance on the scene. The Magyars were originally from the western steppe, probably somewhere in the general vicinity of the Black Sea, but in 900 they had migrated to the Carpathian basin, a large and fertile plain where they could graze their horses. Attila had used the region similarly nearly 500 years earlier, and like Attila and the Huns, the Magyars would strike out from the Carpathian basin, pillage their enemies, and then return home with their spoils of war.

East Francian defeat at the hands of the Magyars was a yearly affair from 907-910 AD, with multiple armies being annihilated. For the next several decades the Magyars would continue their successes against West Francia, East Francia, Italy, and Burgundy. Large swathes of these kingdoms were forced to pay tribute and some even fought alongside the Magyars.

However, the tide started to turn in 933 at the Battle of Riade. East Francia had just elected a new king, Henry the Fowler, but given the decades of turmoil, his position was hardly secure. At Riade, Henry scored a victory against the Magyars, securing his position as King of East Francia. His son, Otto, would ride this momentum and finally score a decisive victory against the Magyars in 955 at Lech.

This earned Otto incredible legitimacy in Christendom, what with its power centers in Italy having been under threat and attack by the pagan Magyars for the past half century. Otto would later launch a campaign into Italy, bringing northern Italy into the fold of East Francia, which he leveraged against the papacy for an imperial coronation. In 962, Pope John XII crowned Otto I, bestowing on him the title "Emperor of the Romans." Thus, the Holy Roman Empire began coming into existence.

The Magyars, meanwhile, no longer threatened Western Europe. Instead, they directed their aggression southward toward Bulgaria and the Byzantine Empire. While successful against Bulgaria, the Magyars were thwarted by the Byzantine Empire. In 1000 AD the king of the Magyars, Stephen I, converted to Catholicism, forming the Kingdom of Hungary.

This is a really fascinating time of crisis for Western Europe as it faced invasions of Vikings from the north, Magyars from the east, and Arabs from the south. If you're interested in Vikings then you may be interested in the other ways the region was facing pressure at this time.

Source:

Peter Heather, Empires and Barbarians, Oxford University Press 2009