Any dry branch of a tree can be used as the driftwood. Or any thick roots of trees. Cactus are available in nurseries. Also check in online plant stores like ugaao or mybageecha.
Are you asking about the tulle fabric which I put in between the pebbles and sand? We are putting tht to prevent the soil from getting mixed up with the pebble layer. Regarding the roots of succulents.. they are very tender. Also don’t expect the cacti to grow much in a terrarium.
