Drill jigs are used for

Holds and locates the workpiece

Fixtures are the work holding devices, which holds, supports and locates the workpiece but not guides the cutting tool to perform a specific operation.

Post jig

Post jigs are used for location from a bore.

Plate jig

Plate jigs are sometimes made with legs to raise the jig off the table for large work.

Plate jigs mainly consist of a single bush plate with a provision for location and the clamping of workpiece. So the drill bushes guide the drills.

Pin type locator