Spire by Reveal Sound
A versatile synth with 4 oscillators, effects arpeggiator. The sky is the limit with this one. And it is very stable, I highly recommend you try it out and spend some time getting familiar with it, you won’t regret it.
Analog Lab by Arturia
Arturia makes great plugins! Analog Lab is easy to use and comes with a lot of great presets. Just start making music, and waste no time designing sounds. You can make your own sounds, and you can buy soundpacks, there is a lot to choose from in the built-in store.
Vice by Ujam
No, this is not a synth but a great beatmaker. I use almost all of the beatmakers from Ujam. They are easy to use and sound great, so they are my go-to when making music. Ujam also makes synths that sound great which I recommend you check out.