Tabletop-Art has their Swampland Bases available in a handy new starter set.
From the announcement:
4 x 50mm Base
5 x 40mm Base
25 x 30mm Base
Nice swamp style baseset, 180 degree view marks are inserted in the base.
The painted bases could be filled with water effect to get more swamp looking.
The matching swamptemplates can you find here: Game Accessorires