I know a friend who is a Notary Public and does "signings" for $100-$150 each. She gets calls from (usually) Lenders who ask her if she is available at a certain time/date/area of town. She can accept or decline as her schedule allows. She downloads and prints the closing/refi papers and takes them to the signers house to witness their signatures. Then she sticks them in overnight mail to the lender and usually takes about an hour total.
You have to get certified, so there is some costs up front for that but you can get the training you need in a weekend. Additional costs for legal paper, toner cartridges, gas, and overnight mail costs are also things to consider. Most of her payments come in a month after the signing was made, so it's not quick turn around, but can be steady income once you get going.