Any mod that interacts with a sheet, or that interacts with paths will most likely be a showstopper on a Beacon Sheet or Jumpgate, respectively. Things that interact with tokens or the general interface (Token-mod, Dynamic Lighting Tool, Simple Sound, perhaps Roll20Audio Master, for example) will probably still largely work with a few small exceptions. Unfortunately, many of the most popular scripts are pretty much dead right now. This includes things like ChatSetAttr, Group Check, Apply Damage, half of Reporter, Group Init, It's a Trap, Combat Master, Customizable Roll Listener, a good chunk of the metascript library, half of ScriptCard's capabilities. Some of these problems might be fixable with updates to Beacon sheets or jumpgate at some point in the future. However, most of them will need to be rewritten from scratch or have parallel code added to handle Jumpgate differences. In either case, there is no current way forward. The tools (some of which are being built, to be fair), just don't exist yet.