First, I'm an exclusive Paid-Meta Content Creator.

In the pursuit of effective mentor and coach acquisition for your startup, leveraging your immediate network is a commendable initial step. However, to optimize your strategy, I recommend a diversified approach. Incorporating cost-effective marketing tools such as social media advertising and posting, engaging in collaborative initiatives, and actively participating in relevant Facebook network groups for potential coaches are integral components. By using these avenues, you broaden your outreach and enhance the likelihood of connecting with suitable mentors. Further amplifying your efforts with live social media marketing can expedite the expansion of your reach. Should you have any additional inquiries regarding your startup journey, feel free to reach out for personalized assistance and guidance.

A good way to get more mentors would be to follow the playbook that www.mentor247.co did.
They're fairly new in the market and seem to already have attracted a large following.
From what I understand they got most of their mentors through Linkedin and some via organic traffic - although the second option takes more time.
Hope this helps.

Here are some low-cost or free ways to attract top-quality mentors for your new marketplace:

Leverage your existing network. Ask current mentors if they have any referrals or recommendations for other qualified mentors they know. Word-of-mouth is powerful.

Post on relevant industry forums and groups on sites like LinkedIn, Reddit, and Quora. Introduce your platform and what you're looking for. Engage in discussions to build credibility.

Contact local universities and colleges. Many have career centers, alumni associations, or professors who may be interested in mentoring students.

Reach out to professional associations and organizations. Groups in your focus areas, like entrepreneurship councils or astrology societies, can spread the word.

Pitch relevant industry influencers or bloggers: Ask if they'll write a post highlighting your platform and mentor opportunities.

Host virtual information sessions - Share details on your platform and directly recruit mentors through Q&A livestreams.

Offer perks beyond money. Highlight non-financial benefits like networking, resume building, and helping others.

Use a waitlist. Get early signups and follow up when you're ready to onboard more mentors in each category.

Think of a situation to see how they respond. Ask them why the responded the way they did. If they can clearly explain how they thought of solution. then interview them if you approve.