Hi there, @TaxCatSC.
Welcome to the Community family. Allow me to share some information about searching all the vendors that share very similar names with customers in QuickBooks Online.
Currently, the option to search all the vendors that share very similar names with customers in QuickBooks Online isn't available. You can only search multiple names by transaction. I can see how this feature would be beneficial to your business. I encourage you sharing this idea to our Product Developers. Doing this helps them to assess how we can improve our product and determine what features need to be added in future updates. You can do this by clicking on the Gear Icon and select on Send Feedback Online.
Also to be updated about our latest happenings, updates, and features, I'd recommend checking out our QuickBooks Online Blog. Through this, you're able to know the recent news about QuickBooks Online and what our Product Care Team is working on.
In case you need additional assistance, feel free to reach out to our Customer Care Team. You can reach through this contact details:
Please let me know if there's anything else I can do to help. I'll do my best to provide further assistance. Happy weekend!