How to implement GSW13 using Helib or SEAL?
A good resource for FHE implementations is found on Micciancio's website. Searching GSW on it points to FHEW/TFHE, although they are quite different than "standard FHE" schemes (they bootstrap after each gate in the circuit). They are implemented though.

Besides those, there are various libraries for lattice crypto (Palisade, Lol, NFLlib, all on the linked webpage) which may be useful to use in any given implementation as a starting point.