Judges 3:31 (ESV)
31 After him was Shamgar the son of Anath, who killed 600 of the Philistines with an oxgoad, and he also saved Israel.
Judges 12:8–15 (ESV)
8 After him Ibzan of Bethlehem judged Israel.
The threefold sequence of minor judges (Judges 3:31; Judges 10:1–5; Judges 12:8–15) provides a geographical pattern that moves from south to north:
Judges 3:31 pertains to the south, as it deals with the Philistine threat.
Judges 10:1–5 is oriented toward the Transjordanian (at least for Jair the Gileadite)
Judges 12:8–15 is oriented toward the north, as it deals with Zebulun and Ephraim/Manasseh.1
1 After Abimelech there arose to save Israel Tola the son of Puah, son of Dodo, a man of Issachar, and he lived at Shamir in the hill country of Ephraim.