There are a lot of programs that can be found here:
https://www.latticesemi.com/en/Products/DesignSoftwareAndIP
Which of these do I need for creating a design with iCE40 LP FPGA?
The reason for my confusion is that we merely need Quartus Prime for Intel and Libero SoC for Microsemi. However, when it comes to Lattice Semiconductor, there is a lot of choice.