Hi,
There are several ways to get a No Blood keychain including on sites like eBay where you can order a tag with any wording on it that you wish and at very good prices. Some of the pet tag sellers have a medical alert tag that can be engraved with your choice of wording; I have done this myself and they turned out really well.
But one company online which sells ready-made keychains is:
www.mjcmjc.com - this small company sells a keychain and a bracelet which are well made and very reasonably priced - in my opinion. I have ordered from them myself and been very pleased.
Hope that helps.