Battery and other parts

Can anyone recommend specific places to buy e.g. batteries for librebootable devices?

And if particular products can be recommended, that would be a great help too.

My request has two purposes:

1) I am generally looking for this kind of information for the forthcoming librebootable.info wiki

2) I am personally looking for batteries for a Thinkpad x200 and a MacBook 2,1 (A1181)