I'll speak up, although I have not *had* an unassisted, I am on my way to my first one.
While preg with my last, and was learning all about birthing unassisted, I too wondered what preparations could be made. It was a big what do I do? What do I get? What do I need.
I figured out that you don't need anything but your birthing body.
Then trust in birth, body and baby...Actualizing of any fears you may harbour. I am calling it clearing out my cobwebs =) I still learn something new every day on my own personal journey. Focusing on healthy eating and yoga and walks for me is something new I am doing
On the more practical end~
Many people like to read up on the nuts and bolts of birth, what do "in case" of this or that.
many people just read lots and lots of unassisted birth stories. That is about one of the most encouraging, enlightening things to do.
Some people get the books written by people who have done it. Laura Shanley, Marilyn Moran, Leilah McCracken are a few that come to my tired preggo head! Laurie Morgan has an e-book for free, and one of my favorites, Birthing The Easy Way by Sheila Stubbs, isn't published yet, but if you order a copy she's more than happy to hot glue gun one together!
And everyone I know has researched to death the stats on home w. midwive vs. hospital vs. unassisted. I can recite in my sleep by now LOL. One wouldn't make such an important decision without gleening all the facts, of course.
As far as "supplies"~
Somethig to tie the cord with. A boiled shoelace left in the pot until needed is common. Some people made a special pretty tie out of embriodery floss. Lotus birthers don't need anything for this.
Towels warmed in the dryer are said to be very nice. Why not throw the recieving blankets in with them?
A plastic shower curtain to lay under the bedsheet, or a cheap plastic table cloth.
Some get nasal aspirators, but my druthers are not to, for myself anyhow.
a newborn hat.
Those plastic sheets with the absorbant paper, Chux pads.
Any kind of container to put the placenta in.
Im rubbing my eyes, I hate to say! I hope I answered your question in the way(s) you meant. Best wishes on your path to a beautiful birth!