Tree Growth Library
Within OpenCog and it's components, there are several occurrences of Rules that are then applied to create some output. Instead of replicating code in multiple places, it'd be worthwhile to have a one system that carries out this process.
Also, the selection of what Rule to apply, and the growth of a tree that consists of a series of Rule applications could be generalised (and specialised by individual components as necessary). The heuristics used for growing the tree could also be shared or specialised.
The components that could benefit from this library are: