M-Tron Pro - Complete

Disclaimer: the following is one carbon-based biped's subjective opinion, and should be treated as such

I personally don't need 13.5 GB worth of boutique flavors of Mellotron- but if you're a completist/devotee of the Church of 8 Seconds, I couldn't recommend anything else.. M-Tron in some form has been around for quite a while, which, in the context of "Does the dev actually care?" is a very good thing; the fine folks at GForce have probably spent more time thinking about Mellotrons than I've spent listening to them over the years (that's a lot of "What's Going On", "Strawberry Fields", "Nights In White Satin", etc.).