I'm working with a startup and would like to know some different channels through which I can promote it.
It really depends on what the startup does and what their industry is. Can you expand on your question?
It's a product called elink.io. Mainly a SaaS product focused on helping individuals create newsletters, web/blog content, single web pages through content curation.
You can say that website owners, bloggers, creative individuals who need to build portfolios, business/individuals looking to create curated newsletters would be our target audience.