list available parameters of variable Is there a way to print all of the available parameters/handles when I set a variable? 

For example if I put {% set orders = craft.commerce.orders.find() %} is there a way to list out the available parameters/handles depending on what I set, without having to go to the docs? So a way of checking that my code is right from the templates.
If you're looking for a purely Twig/template solution, then your best bet would be to either enable devMode and use Twig's dump() method or install something like the Craft Kint plugin.

Keep in mind that both of them are going to give you much more information than just attributes available on a model (like the array of OrderModel's your example is going to return), but that info will be included.