Hi Ana,
I started online in June. I would say a notebook to keep track of your progress, at least that’s what helps me. Definitely a yoga mat because some modules are more involved than some, so you’d need it to practice. I use blocks to help me with alignment but it’s really up to you and where you are in your yoga journey. Props are fun and they help a lot to avoid injury. I also got a few of the books they recommended only because I love to read and it’s also good to mix things up while studying. Hope this helps, all the best!