....DomainTools is pretty good, if you don't mind paying the fee....Others may have good suggestions.
I know that right now you're focused on tracking down what you own, and where, but, when you find them, you need a system to keep track.
Many people keep a simple excel spreadsheet, that lists across the page - for each domain - something like:
Domain name
Name of Registry
Date acquired
Expiry date
Where its parked (if it is)
What you paid for it
When you sold/dropped it
What price you sold it for
Parking Revenue per month
Comments/Plans - eg 'Develop', 'Sell', 'Park', potential sale price etc)
At a glance, you can see exactly what you've got - and where - all in one place, at any time....Plus, this also enables you to easily total how much you've spent on buying domains, + how much revenue you are getting, at any one time, from domain sales, parking, or other sources.
...And, back this info up regularly, so, its not lost if your comp crashes.
Sounds hard to do....but, it doesn't take much time to keep up once you've set it up, and got all the domains listed....The trick is to update the spreadsheet each time you buy, sell, or drop, a domain.
This way, you know where you're at, at any one time.
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