This is an amazing list. I will +1 Dexed cos FM is great, and add a few more music production apps to the list.

BBC Symphony Orchestra Discover - A great all-in-one orchestral vst with decent samples. Great for people wanting to bridge the gap between writing with sections and writing for specific instruments. Lacks articulations like Legato and Marcato, but is ridiculously good for the price of jack shit

SPAN - An excellent mixing and mastering vst that gives you a highly configurable fft spectrum analyzer, with a few presets for translation checks. My favorite feature is the correlation meter, which helps me visually check interference in stereo mixes

Kontakt free library - Has some solid samples for a selection of instruments, but I mostly use the Jazz Guitar and Bass Guitar from here for basic sketching

Equalizer APO - System wide EQ. Extremely configurable. I've since hopped over to SoundID Reference, but prior to that, I was using this. It's great for making all your headphones and speakers sound like any other pair of headphones, and there's a huge library of headphone presets that tell you how to get a neutral signature on just about any pair of them