Greenland

It is really interesting to still see SynthEdit based plugins being released to this day. Greenland is a wonderful subtractive synth. It comes with many of the features you would expect including a solid number of waveforms, FM, and unison all wrapped in a really nice looking interface. Much like Backflipper (also from DC2026), it will kill the framerate of FL Studio unless bridged. This developer is also the author of another fun synth called "Diatonica" which I would also recommend giving a try.

Update: I did try the recommended fix of enabling the Fast Idle setting, however it still does have framerate issues. Still a great plugin, it mainly has these issues in the oscilliscope, meter, and keyboard so it is far from unusable.