I & II Samuel: David and Attack on Titan (or Eren and Goliath)

There are many parallels between Attack on Titan and the Samuels. David came from humble beginnings as a shepherd. Eren Jaeger, the main character of Attack on Titan, was orphaned as a young man. Eren, like David, shows incredible courage and passion when fighting his enemies. The Germanic town of Wall Maria in which he lives, originally was very peaceful but gets destroyed one day by an unforseen Titan attack, and from then on is constantly under the attack by the Titans, much like the people of Israel are in constant battle with the Philistines. Israel can be paralled with and the Titans represent the Philistines. Titans are just what the name implies, giants, with an appetite for human flesh. The bigger the Titan, the more ugly and hideously disfigured they are, unless they are an "abnormal" in which case, anything goes. 

Eren Jaeger (or Yeager), Attack on Titan
Jaeger means hunter in German

Eren, like David, was able to stand up to his giants, slaying at least 20 of them. Whereas Saul was merely jealous of David, Eren was legitimately feared because he was able to turn into a Titan himself. This caused the humans of Wall Rose to greatly distrust him. This can also be paralleled to when Saul had pushed David so far out of Israel that David ended up fighting for the Philistines. The Philistines mistrusted David because he had slain so many of their own people. Although Eren is able to turn into a Titan, he obviously is not a traitor to his people although they are so terrified of Titans that even though he fought for them, the fact remains that he may not be able to control his Titan form. Eren ends up joining a special division of the Survey Corps who slay Titans. Eren joining the ranks of Titan slayers (to me) kind of alludes to David slaying 10,000s. 

Another allusion to David is killing at a young age. David was able to slay lions and wolves to protect his flock. When Eren was young, kidnappers came and killed his friend Mikasa's parents. In order to protect themselves, Eren and Mikasa brutally murdered the kidnappers. 

This is all within the first and second season of the anime. There may be more parallels and allusions, but I also dont want to spoil too much of the plot (for you or myself because I havent finished watching all the episodes to date).