Technic, Pin Connector Round 2L with Slot (Pin Joiner Round)

Technic, Axle and Pin Connector Hub with 2 Perpendicular Axles

Technic, Axle and Pin Connector Angled Triple - 120 degrees

Technic, Axle Connector 2 x 3 Quadruple

Technic, Pin Connector Perpendicular 2 x 4 Bent

Technic, Pin Connector 3L with 2 Pins and Center Hole

Technic, Driving Ring Connector 3L