Epic hero point and talent affixes is +10 but the cap is up to 40 really, just like the hero points. Same with epic talent affixes +10 and the cap is up to 40 because in PvE, talents cap is 40. In PvP, epic +10 becomes +4 or so.
If you're talking about Elixir however, All Skills cap is 12 and same with All Talents. However the actual affix itself is +5 talent or +5 skill . In PvP that appears as +2 and cap is +4.
All sets cap is 4 in PvE but 2 in PvP.
As far as sets, cap is 8 in PvE when you add 4 set slots with the same set and use 4+ All sets. In PvP, cap is probably still 8 for one set affix in all 6+ years but nobody in their right mind would only fill their gear with one set only all around with +2 All sets.
The actual All Sets cap is 4 in PvE but 2 in PvP.