I really liked Psystem 1. It's so clean and can be done literally anywhere with nothing. The only
issue I had was the instructional video felt a little unclear and confusing. You'll probably need to
watch it multiple times to understand it, but it clicked for me the next day. It's also very
reliable which is rare for propless mentalism. Note that you can swap out the items for whatever you
like, and this does require some time to memorize everything, but he gives you a very easy way to
memorize it.
Overall, I definitely recommend this. When someone wants me to read their
mind, but I have nothing on me, this might be the effect I do.