ANDT is a tool by Andibad composed of a few different features, some of which work on both Gen 4 and 5. According to the description it is deprecated but I wasn't able to find a more recent version. ANDT has the ability to modify movesets, evolutions and experience tables on Gen 4 and 5, wild encounters on DPPt and Hidden Hollow encounters on B2W2. As far as I know this is the only Hidden Hollow editing tool out there, so I would recommend this tool just for that. I've not personally used it but I believe I've used a standalone version of the hollow tool before (which no longer exists) and it worked great.