Since everything a toddler does become an invigorating learning experience, the images should definitely be of things that they recall, if they can name it, the better. Toddlers learn better through visual examples and what better way to do this if not with coloring pages. Hence, you can use coloring books to teach more to the toddlers than just colors, you can do the alphabet or count numbers. The alphabet or numbers can also be big enough for the children to do some coloring on them too.
A lot of the activities kids do these days are very expensive or very hard for me to join in with. For example, I certainly can't skateboard, I can't swim and I definitely do not know how to use a PC or Xbox to play games. I am lost when it comes to computers, I really am. I know it is inevitable that as my son grows that he will soon enough be wanting to do things on his own and being seen with his dad would be grounds for teasing from his friends so I am making a huge effort to spend as much free time as I can with him now and really make every moment count. They say time is the most precious gift you can give to a youngster and I am trying hard to live by that. It seems increasingly hard to find activities that Fathers can do with their little ones. Mums seem to get most of the fun.
In the end, coloring is soothing. There are so many proofs and studies on that. When something soothes you, it cannot be harmful. So, this must be a good reason to seize this as an opportunity to make your crew at the company both positive, cheerful and stress-free or encouraged to cope with their work.