As mentioned there are dozens, and Wikipedia will show you[0]. Since CRMs can be bolted onto just about every business, use cases vary extremely. If I'm being honest, every sales manager starts with an internet search to find the latest rundown [1].
My recommendation is to set aside time to play with a lightweight (pipedrive) + heavyweight (Salesforce) options to see how you might use them one day. I would treat CRMs like a regular piece of software. Many offer totally free trials for 1-3 users. So I would bet they agree with this approach :)
There are zillions of all sorts of vendors, however it will most likely boil down into these: Oracle,Salesforce,Adobe,Microsoft,Zoho,Hubspot,etc. Some interesting resource on CRM in general:
https://beagleresearch.com
As for specific products,I'm mainly familiar with Salesforce,so:
https://trailhead.salesforce.com/en/home