Everyone is different on their likes and interests when it comes to ABDL stuff. Some will feel little with a bottle, and others don't want any part of a bottle and prefer cups or sippy cups. You might take a walk down the baby / toddler isle in the store and see if anything pops out at you, that gets your attention.
I've got onesies, bottles, sippy cups, sleepers, plastic pants, pacifiers, etc. For me I don't really care for much of it, and don't really use any of it. The exception is sleepers. I always feel really happy when the weather gets cold enough that I can start to wear a sleeper again at night. Pacifiers are another thing that I like too. I sucked my thumb for almost all of my life. So using a pacifier is comforting to me.
Whilst all the material suggestions are great, there's also a human aspect involved in this, so I'd say look for play mates or a caretaker even in your area. I'm stressing the in the area part to save you stress in the long run. Also, be active on this website to meet some people to just talk to here or on Skype or any other media of that sort.
You can get whatever would make you feel like getting. All of us are different in what we want to don't want. Personally for me I like being in diapers hugging my plushi while sucking on my paci or drinking from my bottle.