Instrumental only music and some of it is really great for beginning, end, and background music for training. Royalty free, and big selection! They specifically indicate you can use their music for a 'variety of projects'.
Ever have trouble picking color and a color pallet? This site does all the heavy lifting for you providing your pallet based of an initial selection and then all the details you need to implement it into a dominKnow theme.
Creating an impact with images is not just about selecting the right image. This article gives some useful tips on how selecting cropping can have a positive impact on the images used in your training.
xAPI or How I Learned to Stop Worrying and Love the Spec