Only use toys on elevated shelves when they are appropriate for that setting and do not interfere with footing or encourage uncontrolled lunges near an edge. A loose rolling toy can turn a resting shelf into a difficult play surface.
Dangling cords, ribbons and improvised attachments can create separate hazards and should not be added casually. Follow the furniture manufacturer's guidance for any built-in toy and inspect it for damage. Interactive play is often easier to manage in a clear floor area where the cat can move without a height-related obstacle. If you use a reward to introduce a shelf, keep the activity calm and close to an accessible level. The main role of a high resting shelf is secure, comfortable access and rest; it does not need a collection of accessories to be valuable.
A small ball that is harmless on the floor may roll straight off a shelf during play. Use the setting, not simply the toy's label, to decide whether an activity belongs at height.
For product comparisons alongside this advice, see SkyRoute wall climbing set and Feline Sovereign Spire. The details below explain their sizes and uses.
Further reading: vcahospitals.com; cats.org.uk.
SkyRoute wall climbing set
Feline Sovereign Spire