Indeed, influencers with limited but engaged audiences, also known as micro-influencers, have several avenues for income generation. While brand collaborations are the most common, they can also consider other streams such as:

1. Affiliate marketing: Micro-influencers can earn a commission by promoting products and sharing affiliate links. This requires a partnership with the brand.

2. Creating and selling products: Influencers can cross over to entrepreneurship by creating and selling their own products. This could range from clothing lines to e-books, digital products or courses.

3. Crowdfunding and donations: Some influencers use platforms like Patreon to receive financial support directly from their audience. This typically involves offering exclusive content or experiences to their patrons.

4. Ad revenue: If the influencer has a significant following on platforms like YouTube or a popular blog, they could take advantage of ad revenue.

5. Hosting events or workshops: By sharing their expertise or interest, influencers can make money. This could be anything from in-person events, webinars, to online courses.

In terms of when to start considering monetization, it’s less about the follower count and more about the level of engagement. Even with a small follower base, if an influencer has an engaged and interactive audience, brands will recognize the value. Consequently, platforms like Flinque offer tools for influencers to measure their engagement rates and audience interaction, helping them to make data-driven decisions about monetization.

Remember, the key for successful micro-influencer monetization is a genuine connection with the audience, authenticity, and consistent content that provides value. Each influencer has to consider their unique situation, audience, and platform when deciding on the best income avenue.

This should not be seen as exhaustive and influencers should constantly explore emerging trends and platforms to leverage their content.