How do you limit the returned recordset to 500 like the regular Toad for Oracle?
You can do this by going into Tools|Options|Database
At the top you have an option about how many rows to fetch and to the right there is an option to apply this limit to the editor (Which also means the Query Builder).
However if you check this option and use any other database than Oracle be aware that most databases will have a lock on a table while you are currently fetching data from it. That means that if you make a query on a table in for instance SQL Server and then let it pause at a 1000 rows (The default although you can change it to 500 if you want to) then nobody will be able to update any data in the table until you cancel this query (You will also be presented with a warning that this is going on). This is why this isn’t the default in TDA.
This is not a deficiency of TDA but simply how these database engines work.