For just playing with chords, there is also Key Chords, which you can trigger with a mouse and make progressions with. It is nice to have chords locked to specific keys if you are doing song writing, and is a simple web app so can access it from anywhere. The author went so far as to add a MIDI export to it a few years back to help with folks who wanted a MIDI track (rudimentary) to start with for driving VSTis.

abacab
Cthulhu has a chords module for playing chords with one finger.  Cthulhu can generate sounds, or it can route MIDI to another synth plugin.
 
Demo available, purchase for $39.
 
https://xferrecords.com/products/cthulhu
 
Cthulhu VST/AU Demonstration
https://www.youtube.com/watch?time_continue=107&v=3t2yD1kX2_w

There's a Cthulhu Masterclass video series from ADSR. They also have a number of preset packs for Cthulhu.
 
https://www.adsrsounds.com/product/courses/cthulhu-masterclass-tame-the-chord-arp-monster/
 
https://www.adsrsounds.com/synth/cthulhu/
 
'Masterclass' is a bit of an overstatement, but for $19, it's helpful enough.