Relational RL has not made a lot of splashes in real-world because it is easier to write a planner than learn a relational RL agent. This might be about to change with the current achievements of the graph based relational reasoning approaches. This article summarizes my understanding of the pioneering work of Vinicius Zambaldi et al. (ICLR 2019) on Deep Relational RL.
Overview of Adam Santoro et al. (NeurIPS 2017).
My notes on Džeroski, Sašo, Luc De Raedt, and Kurt Driessens, Machine Learning 2001