Right now, can't get you the links, sorry. But here is some ideas:
1. Plants - carex (sedge), hosta, spider plants, boston fern.
2. Halves of plant pots, buried in the substrate.
3. Sewage pipe (T-shaped connectors, for example).
4. Cork bark pieces (they can burrow under) and half logs.
5. Dishwashing tubs or plastic boxes with an opening cut on the side.
6. Flat stones (slates) put together to make a "bunker".
7. Tree branches or roots, can be fresh cut with leaves to provide canopy and snack at the same time (mulberry, hibiscus, grape).
Do not add all of these at once to avoid clutter. Start with hides on warm/cold sides, add a shady plant in the middle and see how it goes.
