The ornamental design for a stand for displaydevice, as shown and described.
1. Stand for display device
1.1: Perspective
1.2: Rear perspective
1.3: Bottom perspective
1.4: Front
1.5: Back
1.6: Left
1.7: Right
1.8: Top
1.9: Bottom
1.10: Enlarged
1.11: Reference
Reproduction 1.10is an enlarged view of portions of reproduction 1.1; reproduction 1.11shows the state of use; the broken lines depict environmental subject matter and form no part of the claimed design.