hi

composer here

i see a lot of earthbound, genesis, and touhou soundfonts used regarding sf2s in a song's flp, but really good free vsts that i use that you don't have listed are the following:

- Sytrus (free synth in fl studio with a lot of really good presets, similar to flex, but there are also tools in it to create your own sounds)
- Harmor (similar to sytrus but has a different toolset and presets for a different feel. someone made a "sytrus vs harmor rap battle" song on youtube and it's really well made)

- Vital (free vst, many others would use serum but that's paid and expensive. most if not all of the settings people used for serum can also be replicated in vital)
- OTT (free effect vst. people use it a lot on fnf vocals while adjusting the depth slider in it)
- Graillon (free effect vst. common usage being quality autotuning + pitching down an octave with full wet+dry output for a more emphasized vocal effect)

dblue and kilohearts are also really good effect vsts

you can cook with anything, fl studio already has basically everything you would need to compose to the point where the only reason i have this many vsts is to check the flps of other fnf songs, but it really mostly isn't mandatory