TS-404 by Sonic Syndicate

This is the standalone precursor to the synth that is now part of FL Studio. 2 oscillators with FM, ring modulation, sync, and raw audio file loading, a filter with 4 modes, step sequencing, and disk streaming. Up to 4 synths could be run and linked in a single instance. This was probably my favorite soft synth for a good long while after I first found it.

It's been a long time since I tried FL Studio, but the last time I tried it (this was when it was still called Fruity Loops), I remember noticing that version of TS-404 sounded a bit different. I wouldn't be surprised if it's changed more since then. So, even if you use FL, it might be worth checking this out, just for the fun of it.