Moneytane
Agree, children's art belongs on a fridge or classroom walls, not coins and stamps.
As for mine, take your pick from these beauties.

Dictators never look pretty

This fish is pretty ugly - Jaggerius megalippus?
Ugly for being a racist genocidal demon
I love the history to be told through coins! It was pointed out to me on another thread, rightfully, that the "dictator" category needs to be approached tactfully, and it is one of the categories that I also want to develop.
Julius Nyerere was considered as the founding father of Tanzania, and was well loved by its people. He was instrumental in overthrowing the Ugandan cannibal Idi Amin, but remains controversial from a Western perspective for his anti colonial and socialist views.
Paul Kruger was a Boer leader best known for his role in the two Anglo Boer wars. This predates Apartheid in South Africa and he remains, with little local controversy, the head on modern South African bullion (Kruger Rands).
Leopold committed unspeakable atrocities in Belgium Congo, and his court directly took profit from it. If you want to read more about Africa, I recommend looking at the Mau Mau rebellion (Kenya), German South West Africa (Namibia) and the reporting of Emily Hobhouse on the the second Anglo Boer war (South Africa). Those may provide a few more heads for your ugly coin collection 😆
Most recently, you could follow the current efforts of the AU to get colonialism recognised as a crime against humanity alongside slavery, apartheid and genocide. That could really add a lot more heads to your section!
The fish may be a Coelacanth, once thought extinct until rediscovered in a fishing net off the coast of the Eastern Cape, where I am from.