Why yes!
Terracotta pots, old pipes, large rocks (washed with clean water and no soap) bits of old wood, and lots and lots of plastic plants! The more plants the more natural and colourful and interesting the tank becomes. I have found purchasing a tank backdrop or poster will help a lot. It’s a long poster with weedy underwater designs that you stick to the back of the tank.
You can even grow live plants in the tank, which is great for water quality too. Java moss is great and you can train it to stick to things. You can even grow houseplants out the top of the tank water, Peace Lilies work well, you just have to make sure you get ALL the dirt out of the roots.
I prefer a more natural look but if you want super funky you can get fluro coloured sand and crazy colourful plants. I just find the more stuff, the better it looks. Good luck, post pictures!