You can get a wax "burner" (it doesn't heat above skin temp) and add drops of essential oils to the wax. I do that when the blocks run out of scent and actually prefer it to the Scentsy scents. There are bunches of natural wax blocks on etsy. Natural candles on etsy too.
1 part vodka + 2-3 parts water + essential oils in a mist bottle is a sort of homemade Febreze. It works really well. You can do something similar in a reed dispenser, but I think that's straight vodka. My cats try to eat the sticks, so I can't use those.
Simmering water + lemon + rosemary + vanilla smells like Williams-Sonoma stores. Works in a crock pot too if you're absent-minded like me and don't want to boil the pot dry. I have a tiny dipper crock that came free with another.