I've been using names from the Mr. Men series of books, so e.g. tickle, grumpy, topsyturvy, daydream. Easy to remember because the characters are each so unique

I've been using names from the Mr. Men series of books, so e.g. tickle, grumpy, topsyturvy, daydream. Easy to remember because the characters are each so unique and different, and gives each machine its own personality: "Oh crap, grumpy is acting up again", etc.