In terms of substances, cigarettes, benzos, opioids, painkillers in general. I had a brief stint with cocaine but it ended up being too difficult and expensive to procure; didn't seem worth it.
Fun fact, my addictions are purely psychosomatic; I generally don't feel any withdrawal symptoms. I've quit opioids and cigarettes cold turkey with barely any ill effects twice despite both nicotine and painkillers having well-documented withdrawal hells. It's no coincidence that I only managed to do so once it seemed like life was getting better, and also no coincidence that I fell right back in as soon as things started getting shitty.
In terms of interests and behaviors, video games, sleeping (good practice for being dead), and as of late, hanging out here. I dunno, I just like y'all.