I have one of these: SparkFun Tiny AVR Programmer PGM-11801. I was thinking of getting another one or two for backup, but there’s probably no need at the moment.

Also I figured out how to put a programmer on my Pluggable ATTINY Development Board For ATtiny13A/ATtiny25/ATtiny45/ATtiny85 Programming Editor Micro Usb Power Connector (see that link for details).