So I have a windows based system with a MSI motherboard that has the thunderbolt addon connector and says it is thunderbolt capable. However i think I'm blind as I have read through the manuals and contacted msi directly to get more information with not much success. Msi has stated they don't sell them and that I could purchase a generic thunderbolt addon from new egg. Has anyone tried a generic thunderbolt addon and would it work?
Motherboard
Z370-A PRO
Thank you

Your motherboard has a Thunderbolt header (right beneath the second full-length PCIe slot).
 
You can try a different brand Thunderbolt-3 add-in-card:

• Asus ThunderboltEX 3
• AsRock THUNDERBOLT 3 AIC
• GC-ALPINE RIDGE

This should work... but it's not guaranteed.
Best case scenario is to the same brand motherboard and TB3 add-in-controller.
 

I know, very odd that msi sales would not have one. I tried 3 times to contact them at different times thinking maybe they were incorrect. Thanks for the insight.