The Alliance of Professional Health Advocates (APHA)
APHA is a network of independent patient advocates and care navigators. They offer a robust directory where patients and caregivers can find local professionals specializing in medical navigation, billing, insurance, and eldercare support. I've worked with these folks for years. They are excellent at what they do.  In fact, they really taught me everything I needed to know about advocates while practicing medicine.
Website: aphadvocates.org

Solace
Healthcare advocates on Solace are fully covered by Medicare and many Medicare Advantage programs. Check your eligibility to see if you qualify—it only takes a minute. Solace Advocates are experienced physicians, nurses, pharmacists, and other healthcare professionals from a wide range of backgrounds. They’ll make the calls, schedule the appointments, and keep your notes organized. They’ll translate complicated forms, keep your doctors coordinated, and be there to listen when you need them most. They can even lower your medical bills. 
Website: https://www.solace.health

AdvoConnection
This organization offers a directory of private health and patient advocates who can assist with medical navigation, healthcare decision-making, and coordinating care. They connect patients with experienced advocates to support them in understanding their options and making informed decisions. I've worked with these folks personally and really like their honesty and commitment to helping others.
Website: advoconnection.com

Aging Life Care Association (ALCA)
Formerly known as the National Association of Professional Geriatric Care Managers, ALCA members are specialists in eldercare who act as advocates and guides. They help seniors and their families manage health, legal, and daily living needs. Their website includes a directory to find local care managers. I've had several members use this agency when they need to find a care navigator.  Excellent and highly qualified candidates. 
Website: aginglifecare.org

Greater National Advocates

This is a non-profit organization dedicated to promoting independent patient advocacy. Their primary mission is to raise awareness about the importance of having a patient advocate and making these services more accessible to everyone. GNA provides a comprehensive online directory where patients and families can easily connect with professional healthcare advocates across the United States. Wonderful people here who truly want to make a difference in the lives of seniors and their caregivers. 
Website: gnanow.org

The Patient Advocate Foundation (PAF)
PAF provides case management services for patients with chronic, life-threatening, or debilitating illnesses. They offer support to navigate the healthcare system, secure medical treatments, and connect patients with resources to handle insurance and medical debt issues. This organization provides a lot of information on healthcare advocacy. Check them out. 
Website: patientadvocate.org

National Association of Healthcare Advocacy (NAHAC)
NAHAC is a professional organization that connects patients with certified healthcare advocates across the United States. They offer a directory of independent patient advocates who can assist with navigating complex healthcare situations, coordinating care, and advocating for patient rights. This organization I've revisited several times. At this time, I do not believe their search button for "Search by Geographic Service Area, Expertise, or Name of the Professional" is working at this time. 
Website: nahac.com

Caregiver's Freedom Club™

This membership program is designed to empower caregivers with expert guidance for a smoother, more rewarding caregiving journey. While it’s not a traditional directory, it offers a wealth of resources, drawing on the expertise of many Care Navigators. Members gain access to expert tips & secrets with new webinars, Q&A sessions, and workbooks added monthly. For a preview of some of the resources available, click here. Join today and take advantage of special savings—click here to learn more.

Should any senior or caregiver need personal service, then check the above directories for a Care Navigator near you.