Benchmark libraries
EvalGM : 3026 discrete optimization benchmarks available in various formats (wcsp, wcnf, uai, lp, mzn). [Hurley et al CPAIOR 2016]
Cost Function Library : an on-going collection of benchmarks from various domains of Artificial Intelligence, Constraint Programming, and Operations Research (formats in wcsp, wcnf, lp, qpbo, uai, opd, and more).