InsideStory Flashcards pegs their site as "the world's most interesting way to learn words." It is indeed a nice repository of free printable flash cards with interesting images that illustrate vocabulary words. About 1000 of these are available to us free through the site, and for a reasonable cost, the site sells boxed sets of vocab flashcards with "Cats & Dogs" and "Animals" themes for human (well, and certainly animal) vocabulary such as malodorous.
a site hosted by the US National Park Service with interactive activities focusing on national parks in the areas of animals, people, history, nature, science, and the parks themselves. No need for a log-in to use the site, but students can become "Web Rangers" with an account
The Alphabetimals characters can spell out any word that you would like. Just type in the word and it will be printed for you., Alphabetimals also offers free printable flashcards, an alphabet poster, and alphabet coloring pages.
caution you can also use it to have it made onto stuff.