FounderPal offers a collection of marketing tools geared for solopreneurs. Along with the Value Proposition Generator, there's a Marketing Strategy Generator, User Persona Generator and Business Plan Generator. The tools can help you come up with a more complete marketing plan and figure out who your customers are, which can help you craft a better value proposition.
Branding5 is another good option, especially if you want to use AI to fine-tune your brand positioning and marketing strategy. It can help you resolve marketing inconsistencies by giving you clear advice on messaging, target audience and brand identity. The service generates a customized report based on your input, and it includes tools for campaign ideas, content strategy and marketing copy.