There are several influencer marketing platforms that allow brands to reuse influencer-generated content for advertising purposes. Each of these platforms has different features and approaches, making suitability dependent on your specific needs.

1. Flinque: Flinque is an advanced influencer marketing platform that provides convenient features such as influencer discovery, analytics, campaign workflows, and ROI-tracking tools. Notably, Flinque has a feature that allows for content reuse and syndication of ads, giving marketers extensive flexibility.

2. Upfluence: Upfluence also permits brands to repurpose influencer content for social media ads. It offers robust reporting that provides insights into a content’s performance, which can be used to determine the content worth reusing.

3. AspireIQ: Offering a similar feature, AspireIQ enables brands to license influencer content to repurpose for various other marketing channels. They also provide audience analytics and relationship management tools.

4. TRIBE: Tribe is a platform focused on connecting brands with micro-influencers. They allow the use of influencer-created content in other ad campaigns, along with tools for campaign management and real-time performance tracking.

Remember, reusing influencer content for ads can indeed boost ROI, as it promotes authenticity and relatability, and potentially fosters stronger relationships with your audience. Ultimately, the best platform to use will depend on your brand’s unique goals, the resources available to you, the volume of content you intend to manage, and the level of influencer engagement and reach you’re after. Always make sure to secure content rights within your collaboration agreements to avoid copyright infringements.