Alchohol blender pens are great for colouring in an image with a really professional look. There are so many out on the market but I am using Spectrum Noir which come 6 in a pack and have a gorgeous range of colours. They can be found in many craft shops and have replacement nibs and refills which means that they will last forever.
This card is a cutie little patchwork badger which really lends to being coloured.
All my cards are available to buy just drop me a line firstname.lastname@example.org