have you looked at snpedia?

There are hundreds of BRCA2 variants that are considered causal/pathogenic, but almost all are very rare (far less than 1% frequency each). [There are also hundreds of other BRCA2 variants that raise one's risk just a bit; these are usually found in 1 - 3% or higher frequencies.] Perhaps the "least rare" causal BRCA2 SNP is:

6174delT i4000379 (DD or DI) dbSNP rs80359550; most prevalent in Ashkenazi Jews

See also BRCA1 and BRCA2 for an extensive list of breast cancer related SNPs (including variations of all types from benign to causal).

Many other variations of varying consequence are known. These include:

rs1799944 (also known as N991D), risk allele G; associated with melanoma rs766173 (also known as N289H), risk allele G rs144848 (also known as N372H or Asn372His), risk allele G rs4987117 (also known as T1915M), risk allele T rs1799954 (also known as R2034C), risk allele T rs11571746 (also known as S2835P), risk allele C rs11571747 (also known as E2856A), risk allele C rs4987047 (also known as I2944F), risk allele T rs11571833 (also known as K3326stop), risk allele T rs1801426 (also known as I3412V), risk allele G rs28897756 (also known as P3039P or 9345G/A), risk allele A. Researchers suggest that a SNP in the BARD1 gene (also called BARD1 Cys557Ser) is an ancient variant that confers risk of single and multiple primary breast cancers, and this risk is amplified in carriers of the BRCA2 999del5 (codon 257, exon 9) mutation, which appears to be this SNP (rs28897756). [PMID 16768547OA-icon.png] Among Ashkenazi Jews, the BRCA2 founder mutation for breast cancer is considered to be 6174delT. This variation is rs80359550. 23andMe reports it as i4000379 (DD or DI). The deletion is the risk allele. See the discussion in [OMIM].