Yes, Spain and Franco owed to Germany somewhat after helping with the civil war, but Hitler coulndīt force them to join the war somehow?!
Except for manpower and Gibraltar I am not sure if there was much else to give, as Spain didnīt seem to be very powerful in any area of army. Training the men to use new weaponry would take a long time, yet better late than never. At least several german divisions could have been moved to more important places by placing spanish divisions instead (french coast, yugoslavia, poland etc. ).
Another country that might have helped was Turkey. If Rommel had won at El Alamein and thus they could have put pressure on the middle east, Turkey might have joined the war and attacked the british in the back. later they would have helped with the attack against russia, I think.
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