If you're talking about what policies are using a certain assertion/entity, it's still possible.
For example, looking for what policies are using Store to cache assertion, you may run a query as below,
mysql> select name from policy where xml like '%CacheStorage%';
Base on that, you may build a tool.
PS: a simple way to find the searching keyword is that, you copy your own assertion from policy manager, and paste to a text editor, you will see the xml format of this assertion, then you will know what keyword is good for searching this entity.
Regards,
Mark