WAGS (Word Alignment Gold Standard) is a benchmark which allows extensive evaluation of WA tools on out-of-vocabulary (OOV) and rare words. WAGS is a subset of the Common Test section of the Europarl English-Italian parallel corpus, and is specifically tailored to OOV and rare words. WAGS is composed of 6,715 sentence pairs containing 11,958 occurrences of OOV and rare words up to frequency 15 in the Europarl Training set (5,080 English words and 6,878 Italian words), representing almost 3% of the whole text. Since WAGS is focused on OOV/rare words, manual alignments are provided for these words only, and not for the whole sentences. 

The resource is available here. For a detailed description, read:

Luisa Bentivogli, Mauro Cettolo, M. Amin Farajian, Marcello Federico. 2016. WAGS: A Beautiful English-Italian Benchmark Supporting Word Alignment Evaluation on Rare Words.
In Proc. of LREC, pp. 3535-3542, PortoroΕΎ, Slovenia.Β pdf.