Overview
The STDCSW2-16M is a crystal made by NDK with 4 pins. - Crystals ROHS.
PCBKit's library has its footprint (EasyEDA_Cloud:CRYSTAL-SMD_4P-L2.5-W2.0-BL_ECS-320-12-36B2-CKY-TR, from EasyEDA), ready for a KiCad board. JLCPCB lists it (part C20010640).
Symbol
The library has no symbol for this part yet.
Footprint
Questions
Is there a KiCad symbol and footprint for the STDCSW2-16M?
Yes. the footprint EasyEDA_Cloud:CRYSTAL-SMD_4P-L2.5-W2.0-BL_ECS-320-12-36B2-CKY-TR, both drawn on this page. PCBKit places them on a board for you when you design with it.
Where is the STDCSW2-16M datasheet?
NDK publishes it: the Datasheet link on this page opens it.
Where can I order the STDCSW2-16M?
JLCPCB lists it as part C20010640, with 0 in stock; the sellers' links on this page open their listings.