There is no definitely new way to restore balance of power within the international system. All “unique” methodologies have been discovered and used at some point in history and what are currently being used today are either the very same things or combinations of them. All of these methodologies fall into the peaceful method with the exception of war and its related methodologies such as compellence, deterrence, etc.. Many, if not all, of these options are available at the start of the situation and the availability of the methods change (some become unsuitable methods, vice versa, and some others either stay suitable or unsuitable) as the situation regarding the balance of power progresses. For a weaker state, war is the final and very last resort of method in restoring the balance of power as it would suffer the consequences of participating in one. The same cannot be said for the more powerful states and hegemons as war is less costly for them compared to weaker states, though they still have to put up with opinions by other states regarding their actions (which may polarize the global system if they are deemed to be in the far wrong side of the decision).
As said, there is no “alternative ways” to enforce/restore the balance of power, any methodology available to the state may be used except for the special case of war which is often held as a last resort solution to the balance of power should all other methodologies fail to do so in the first place.