Today the US Disney Store finally added the new range of core Tsum Tsums to the Disney Store website. These have already appeared in some stores and should continue to show up in more and more stores. So far only the mini Tsums have been released but other sizes have shown up in Europe so it is possible they will be released at a later date.
Here are links to the new Tsums!
Mickey and Friends Mini Tsums:
Winnie the Pooh and Friends Tsums: