Worf

In a parallel universe, Worf was the Klingon chief of security of the USS Enterprise-D during the 24th century.

Locutus
During the Borg invasion of the United Federation of Planets, Picard was kidnapped by the Borg and taken aboard their cube, resulting in Riker taking command of the Enterprise As the crew discovered, Picard had been assimilated into the Borg Collective as his identity was suppressed by Locutus, the emissary of the Borg. After the Borg used Picard's knowledge to easily defeat a Starfleet task force in battle of Wolf 359, Riker devised a plan to turn the tables against the Borg as they proceeded to Earth, entailing the retrieval of the Captain from the Borg cube by Worf and Data. Back aboard the Enterprise, Picard was freed from the Collective as he assisted Data in incapacitating the Borg cube, leading to its self-destruction. (COMIC: Assimilation²)

The Doctor and the Cybermen
While aboard the Enterprise in 2368, the Eleventh Doctor recognised him as a Klingon, but noted that his memories were being altered. Before he saw Worf, the Doctor had never heard of them. (COMIC: Assimilation²)

Bonjaxx's birthday
He attended the Dæmon Bonjaxx's birthday in his bar on the space station Maruthea, as did the Seventh Doctor and Ace and a future incarnation of the Doctor and his companion Ria. (COMIC: Party Animals)