It seems Amazon UK has let out the details of which Simpsons characters will appear in the next LEGO Simpsons Collectable Minifigure Series. This series should be released in late April. The list of all 16 are below!

Homer Simpson
Marge Simpson
Bart Simpson
Lisa Simpson
Maggie Simpson
Grampa Simpson
Ned Flanders
Ralph Wiggum
Nelson Muntz
Apu Nahasapeemapetilon
Chief Wiggum
Krusty the Clown
Itchy
Scratchy
Mr. Burns
Milhouse