Any good books/sources on ancient Germanic tribes?
Yes:
An inclusive study on chimpanzees' social organization (Bernard Lion, 1988)
>>3386773
Germania by Publius Cornelius Tacitus
>Their Children. Laws Of Succession. In every household the children, naked and filthy, grow up with those stout frames and limbs which we so much admire. Every mother suckles her own offspring and never entrusts it to servants and nurses. The master is not distinguished from the slave by being brought up with greater delicacy. Both live amid the same flocks and lie on the same ground till the freeborn are distinguished by age and recognised by merit. The young men marry late, and their vigour is thus unimpaired. Nor are the maidens hurried into marriage; the same age and a similar stature is required; well-matched and vigorous they wed, and the offspring reproduce the strength of the parents. Sister's sons are held in as much esteem by their uncles as by their fathers; indeed, some regard the relation as even more sacred and binding, and prefer it in receiving hostages, thinking thus to secure a stronger hold on the affections and a wider bond for the family. But every man's children are his heirs and successors, and there are no wills. Should there be no issue, the next in succession to the property are brothers and his uncles on either side. The more relatives he has the more numerous his connections, the more honoured is his old age; nor are there any advantages in childlessness.
They were an utopia, when the Aryan race is pure the morals are at their best
>>3386773
Probably not the scope you're looking for, but Empires and Barbarians by Peter Heather talks a good deal about interactions between Rome and the Germanic tribes on their borders as well as the economic development of them from the 1st Century onward.
However, the focus of the book is the Migration Period, so that discussion is largely to set the groundwork for looking at how the Germanic tribes developed.
>>3386804
I have a penguin collection thing of Germania and Agricola by Tacitus
Germania is about the Germanic tribes of course, but Agricola is mostly about his dad who governed Britain for a while but there's also lots about Britain under Roman rule and the various tribes of Britons