1. CVC4 regression test suite.
https://github.com/CVC4/CVC4/tree/master/test/regress
2. Kaluza benchmark suite.
http://webblaze.cs.berkeley.edu/2010/kaluza/
3. Stringfuzz source code, benchmark suites, and supplemental material.
http://stringfuzz.dmitryblotsky.com
4. Z3str2 test suite.
https://github.com/z3str/Z3-str/tree/master/tests
5. Z3str3 test scripts.
https://github.com/Z3Prover/z3/tree/master/src/test