I bought a rotary cutter and extra blades, a large cutting mat (can't remember the size, I got the big Fiskars one), a 6x18 ruler, and small thread snip scissors. When I signed up for my first class I got the smaller 18inch mat and a shorter ruler, think it was a 12x2 just to make traveling easier.
Right after my class I bought the short six inch ruler, a pair of dedicated fabric scissors, a better seam ripper, fine grit self adhesive sand paper (to put on my rulers so they didn't slip), and five million more bobbins. Oh and a sewing box to put it all in.
I'm currently stealing my daughters seam ripper, hers is much better than mine somehow, but I recommend an ergonomic one. I think I bought hers at Walmart, it was a fun color which I figured she'd like, didn't realize it was so much better than the one I had.
Oh, and E.L.F (makeup brand) white handled eyeliner brushes are fantastic to help get all the lint and such out of your machine when you clean it. I've never had much use for the "tools" that came with my machine.