The best places to check to see if you are owed royalties as a session musician are the Sound Recording Special Payments Fund and the AFM-SAG AFTRA Intellectual Property Rights Fund. Both sites have a search feature.

SAG-AFTRA:

Screen Actors Guild‐American Federation of Television and Radio Artists (SAG-AFTRA) is the labor union that represents singers and background performers, among others. Originally founded as AFTRA in 1952, the union merged with SAG in 2012 and currently has over 150,000 active members. AFTRA worked in the interests of its members, primarily in the areas of contract negotiation and enforcement, advocacy (including lobbying, legislation and public policy issues) and member benefits such as employer-paid health plans.  For more information, please visit SAG-AFTRA Membership & Benefits.

AFM:

American Federation of Musicians (AFM) is the largest organization in the world representing the interests of professional musicians. They negotiate fair agreements, protect ownership of recorded music and secure benefits such as health care and pension. For more information, please visit American Federation of Musicians.