I'm a real estate team owner and I'm looking to builld a simple but scalable CRM for my company. I have examples that I can share.
I would have a look at- [login to view URL] & Pipedrive Crm.
Here is an article that will layout the fundamentals of a CRM [login to view URL]
Being a real estate CRM we may not need to incorporate all of these functions but its a good guide.