Hi,
Can anyone provide the list of DO datacenters?
No it uses datacenters provided by global data centers. Like Enquinox or NextDC. https://www.digitalocean.com/docs/platform/availability-matrix/
This is the same for AWS and most other cloud providers.
If plan on having metal servers it would be better to rent Dedicated servers from places like OVH. I have put my own dedicated server into a DC, prices vary and it is not as straight forward as one thinks. You can get charged more for colocation then you do just renting a server from OVH. If you know a guy who works at a DC or at a service provider you might be able to get mate rates which helps massively.