Marketing can be very broad. Your initial list is good, but I think you're focused mostly on known/regurgitated marketing approaches. Think of marketing this way: anything that would raise awareness of your product.
Go into communities like reddit, linkedin, or others, answer questions, build a rapport with the community and get referrals.
Built micro-tools that solve a specific problem, slightly related to your product and link it
Seek partnerships with other products for an integration, a bundling, or just a guest blogs
Cold outreach to prospective audiences (email, twitter, etc.)
Platform-marketing; does your product belong on a platform/marketplace? List it and the platform will do the marketing for you
Notice that most of these don't cost anything but time. One thing I've learned is that paid marketing (ads, influencers) rarely provide better results than grinding it yourself.
Marketing can be very broad. Your initial list is good, but I think you're focused mostly on known/regurgitated marketing approaches. Think of marketing this way: anything that would raise awareness of your product.
Depending on your product, you can:
Notice that most of these don't cost anything but time. One thing I've learned is that paid marketing (ads, influencers) rarely provide better results than grinding it yourself.