About time to start a thread on 2016 standard coins, but to my knowledge no changes are planned to existing designs and no new countries are expected to start minting coins. The last time that happened was in 2010, unless you count the change in mint master mark on Belgian coins - see http://www.eurocollection.co.uk/Marks.html
According to this document (page 4), eurozone countries could change the designs of their standard coins for the first time in 2016, unless the current moratorium on doing so is extended. I haven't heard of any country planning to change their coin designs.
Some news: the mintmaster of the Royal Dutch Mint has changed, so the 2016 Dutch and Luxembourg coins will feature the old mintmaster mark of a sailboat for Maarten Brouwer plus a star to denote the new mintmaster Kees Bruinsma as a temporary mark. A new permanent mark for Kees Bruinsma will feature from 2017.
The Dutch coins have already been issued and here is a photo of the new temporary mark:
Malta seems to be going mintmark mad in 2016:
- the ordinary circulation coins will have no mintmark
- *the ordinary coins in the BU set have an F mintmark in the lowest star as in 2008
- the Ggantija temples coin in ordinary circulation has no mintmark
- *the Ggantija temples coin in the BU set has the F mintmark
- the Ggantija temples coin in its own coincard has the French cornucopia and mintmaster mark
I can only confirm the items with a star so far.