Generate a list of 20 unique and profitable print-on-demand product ideas.  Each idea should include:</p>
<p>* **Product Type:** (e.g., T-shirt, mug, phone case, tote bag, etc.)<br />
* **Target Niche:** (e.g., pet lovers, gamers, bookworms, fitness enthusiasts, etc.)<br />
* **Design Theme:** (e.g., minimalist, humorous, inspirational, vintage, etc.)<br />
* **Potential Selling Points:** (e.g., high-quality materials, unique designs, affordable pricing, etc.)<br />
* **Marketing Strategy Suggestions:** (e.g., social media marketing, influencer collaborations, paid advertising, etc.)</p>
<p>Consider current trends and popular online searches when developing these ideas. Focus on niches with high demand and low competition.  Prioritize products with low production costs and high profit margins.  The output should be structured as a table with the above headings, allowing for easy review and selection of the most promising ideas.  The ideas should be creative, original and avoid overly generic or saturated designs.  Success will be measured by the originality and market viability of the generated ideas, assessed by analyzing current market trends and competitor offerings.