Well back when I was doing it, before we created propertyonion, it was all spreadsheets! Total pain.
When I was wholesaling and also trying to snag foreclosure before it was auctioned I used Zoho CRM to track all the leads.
I think nowadays the advanced lead tracking system like Gohighlevel are popular. For now, did you know they you can create saved lists and saved properties right here in PropertyOnion? here's some videos how:
How to create save searches: get daily updates on any properties that are added that match this search.
How to save properties: Get updates if the propery gets canceled or sold.