Started working on an little ESP8266 project again. This time with an ESP-12 module from Ai-Thinker. Therefor I created an new part in Eagle after the specifications from Ai-Thinker (Technical Specifications).
My purchased module has an slightly different silkscreen as shown in the document. On my module GPIO4 and GPIO5 are swapped and pin EN is labeled CH_PD. That should be checked before using the part.