Hello,

libbitcoin has complete C bindings (for only libbitcoin not the other
libraries) with lots of Bitcoin functionality:

https://github.com/libbitcoin/libbitcoin-c

https://github.com/libbitcoin/libbitcoin-c/tree/master/test
(complete unit test coverage)

And together with the C bindings, there is Python bindings in the works
now too:

https://github.com/libbitcoin/python-libbitcoin/blob/master/test/math_/elliptic_curve.py

https://github.com/libbitcoin/python-libbitcoin/blob/master/test/wallet/hd_private.py

Which also has a ZMQ part for interfacing with libbitcoin-server:

https://github.com/libbitcoin/python-libbitcoin/blob/master/examples/server/fetch_history.py