Outside of Dungeoneering there are very few monster whose Defense levels are high enough that you need to use a specific weapon (Higher tier Dragons, waterfiends and some bosses mostly) so a DScimmy + Ddefender are the best option for general training in fhe 60-70 range, once you hit 70 Abbysal whip + Ddefender is best for attack and defence training, for Strength a Sara sword is best AFAIK. But once you hit 80 attack Chaotic rapier beats them all, no question. Having said that, with the upcoming combat rework it ia possible this will change as Jagex have stated that they want combay to be more immersive and have monsters' weaknesses and strengths actually matter during combat.