The first thing I'd do is change the way you do that: instead of creating a label and two textboxes each time, move them into a UserControl and crate one instance of that in your loop instead. It them becomes responsible for it's content, which keeps them together and makes them easier to find. Add Saldo, Cod, and AccName properties to the new control for access and you're good to go.
Then when you want to find them, just loop through Gb_Bancos.Controls and look for the AccountControl instances:
foreach (Control c in Gb_Bancos.Controls)
if (c is AccountControl ac)
var saldo = ac.Saldo;
var cod = ac.Cod;
Give it a go - it sounds complicated, but it isn't really - and it makes the rest of your code much, much cleaner!