Finding synonyms for the phrase "good influence" can be a challenging task, as it refers to a highly subjective and context-dependent experience. Some common phrases that can serve as synonyms for "good influence" include positive impact, beneficial effect, constructive effect, healthy effect, helpful guidance, affirmative effect, encouraging impact, and motivational influence. Other words and phrases that can be used to describe a good influence include inspiring, empowering, uplifting, edifying, supportive, nurturing, empowering, and influential. Ultimately, the specific synonym used will depend on the context in which it is being used, the intended audience, and the key message being conveyed.