First of all, the TF:G1 episode "Microbots" features an artifact called the Heart of Cybertron, which grants Megatron enormous power. Secondly, the episode "Call of the Primitives" involves all the Transformers with animal modes going to a mysterious planet at the centre of the universe, which is a source of great power and the birthplace of Unicron. This world may be Kandrakar's surface.