If you have a relatively flat area that you do not intend to build houses on, you can make a bit of money by planting Bacteria.
A Bacteria tile with 4 Bacteria neighbors (or 2 moss/house/etc. neighbors) can level up and be replaced with a Moss tile, which brings more money.
A Moss tile with 3 Moss/house/etc. neighbors can level up and be replaced with a Grass tile. A grass tile brings even more money, but also it consumes spice each turn, so consider whether that's worth the trouble.
Underground, you can plant fungi instead of bacteria.
Fungi cannot be "upgraded" like bacteria, but a fungi tile with 3 stalagmite/house neighbors will produce 1 spice/turn, which is a good way to cover needs of a park or create a bit of a surplus for export without sacrificing a greenhouse.
Dump terraforms are generally cheap enough that you can find a tile with a pair of adjacent stalagmites and add a third one. Or plant two extra fungi tiles if you prefer.
