I have found I some files better then others, so make sure you’ve got a good selection of the basics like that, files, buffer blocks, basic manicure tools as well (I like a certain cuticle pusher and pair of nippers as they feel right)
As for colours, acrylics, gels ect. Don’t buy anything till you’ve got your kit and a have chosen your system, as you don’t want stuff that’s going to sit unused
And if your kit doesn’t include one, have a look for a practice hand/fingers to practice your acylic/gel sculpt skills, as yourll want plenty of time to have a practice with l&p ratio and Just general application& finish filing.