Which items are considered most effective in the current Dota 2 patch and why?

In the competitive meta, a lot depends on auras, so items that boost the entire team are effective. An example of such an item is Shiva's Guard, which reduces opponents' attack speed and healing. Also, don't underestimate Aghanim's Shard and Aghanim's Scepter, as they provide significant power boosts to certain heroes.