For “easy” mode I went with some of the top words from the list of most commonly used passwords. For “medium” – same, but closer to the bottom of the list. And for the “hard” mode I went to “word of the day” section on dictionary.com
Easy:
• Password
• Qwerty
• Dragon
• Shadow
• Monkey
Medium:
• Breakaleg
• Opendoor
• Runaway
• Matchbox
• Playstation
Hard:
• Langlauf
• Autodidact
• Trangam
• Euchred
• Imponderabilla