"I would think/imagine/hope etc." are all phrases used to express uncertainty or speculation. When uncertain about something, we often rely on such phrases to convey our thoughts to others. However, using the same phrase repeatedly can make your speech or writing repetitive. That's where synonyms come in handy. "I presume," "I assume," "I believe," "I expect," and "I reckon" are some alternatives to "I would think." Similarly, "I visualize," "I conceive," "I picture," and "I envisage" can replace "I imagine." For "I hope," try replacing it with "I yearn," "I desire," or "I long for." Using synonyms can add variety and depth to your language, making it more engaging for your audience.