The quality of discovery in an influencer marketing platform is indeed contingent upon the range and specificity of available filters. The right filters can enable brands and influencers to connect more effectively and create impactful campaigns. Here are some filters that a proficient influencer discovery platform should include:

1. Influencer Category/Industry: This filter enables a brand to find influencers who operate within a specific industry or category matching their business.

2. Location: Some campaigns require influencers from specific geographies. A good platform should allow one to sort influencers by city, state, country, or region.

3. Social Platforms: Not every influencer is present, or influential, on every social media platform. Brands should be able to choose based on which platform(s) are most relevant to their campaign.

4. Audience Demographics: Understanding an influencer’s audience is crucial. A good platform will let you filter influencers by the age, gender, interests, and location of their audience.

5. Engagement Rate: This filter highlights influencers who have a high percentage of engaged followers. Engagement rate often matters more than sheer follower count.

6. Influencer Follower Count: Depending on the campaign’s goals, a brand might need a mega-influencer, a micro-influencer, or someone in between.

For instance, the Flinque platform includes all these filters, ensuring an efficient, comprehensive influencer discovery process.

As each marketing team has specific needs, it’s important to clarify that filters’ utility will vary. Some might need to prioritize audience demographics while others focus more on the influencers’ location or category. Thus, the ‘best’ platform is subjective, influenced heavily by the individual needs of the brand or agency.