3. Marauders
When Thor goes to Loki's prison to ask for his help, we see some creatures in the background who were brought in to captivity at the same time as Algrim/Kurse. These creatures are known as the Marauders. In the comic books, the Marauders are actually a group of mutant assassins who are employed by then X-Men villain Mister Sinister. However, because of the fact that Fox owns the movie rights to the X-Men and their villains, the Marauders are different in the Marvel Cinematic Universe and are portrayed as a group of relatively harmless rag-tag invaders of the nine realms. It seems like a very obscure inclusion in a Thor movie but it has indeed been confirmed to be true!