What would be the best way to have up to 100 email aliases on the same account?

Is there an email service that lets you have 100 accounts logged in at the same time and you can easily switch them or something?

I need to have 100 email adresses so that I can make many social media accounts for online marketing.
I use bots.

Basically, what would be the easiest way for me to switch between many different email addresses to make quick replies, but also have the mail organised so I know what arrived for each address?

I hope I'm making enough sense here.