Breeding substrate for fruit flies. Just put some water and it's ready. 2 units of drosofix for 1 unit of water.
Springtails, 1 litre box.
wood shavings is usefull for fruit flies cultures.
4 mm tubing
Good material to build your own background.
6 mm tubing
Petri dishes are usefull for many things. Put under coconut shelters, making eggs grow with low water, feeding and growing tadpoles...