These are not unique to Mark, but helpful to consider when examining how Mark constructs his narrative.
Intercalation (putting two stories together in alternating passages)
3:20-35 Beelzebul, and controversy with Jesus' family.
5:21-43 Raising of Jarius's daughter and woman with the issue of blood.
6:7-44 Sending out of the twelve and Herod's banquet
11:12-25 Fig tree incident and Jesus in the temple
14:1-11 Jesus anointing for death and plotting against Jesus
14:53-15:15 Peter's denial and the trial of Jesus
15:6-32 Coronation of Jesus and the trial and execution
Ben Witherington quoted Fowler to the effect that there are 114 questions posed in the gospel with 77 of them going unanswered.
6:21 - 8:26 the two feeding story cycles
8:31 - 10:52 with three weakly organized cycles (8:31-9:29, 9:30-10:31, 10:32-10-52)