These guys do it all. They have a voice-over service (including writing the greeting script) and transfer the greeting to your phone in super high quality. I couldn’t find anything better online anywhere. https://www.okcvideoproduction.com/record-high-quality-voicemail-greeting
Now, we’ve covered the topic a bit at length in the past, with sure-fire ways to engage callers with your business voicemail greeting. Still a solid basis for constructing your new voicemail greeting, we’ll cover a quick recap of the most important aspects of a voicemail greeting for those that are unfamiliar.

Learn how to set up a name recording, default voicemail greetings, and temporary greetings (for holidays and vacations) for your OnSIP voicemail box.
Users often don’t invest enough time into their messages, resulting in incomplete, unprofessional, or otherwise under-whelming greetings. Sure, crafting a greeting doesn’t sound all that complicated; however, there are a number of pitfalls users can fall into—i.e. informality, terseness, sincerity, lack of direction, and more. While none of these sound too catastrophic, they are often interrelated. As such, they tend to worsen any problem. For example, humor can cause informality, worsen ambiguity, and weaken sincerity. That being said, users should strive to avoid ALL these pitfalls.