Recently, the creator of Center for Singers introduced herself to me! What a fantastic resource for singers looking to improve their resumes, check on their audition attire appropriateness, and even learn more about other singers in her Singer Spotlight! If you're in the Dallas, TX area, she offers a ton of in-person services, and offers many online as well. If you need your resumes edited, cover letters proofread, or are looking for a compiled list of music organizations in Texas, you must check her out!
If you're looking for work, you can always consider looking at the Opera America website. This company also lists the tiers of different opera companies, so you can learn whether or not it's a union gig, paying gig, or a "freebie." OperaAmerica.org (Job Index)
My friend, Kristen, started Operaversity a while ago. She offers blog articles, courses, and great information for the Operapreneur - many who are balancing a performing schedule with teaching, side hustles, day jobs, and more! Operaversity.com