Except for an interesting little plug called the "Cloak Hunter Missile," all of what I've done so far was for my own use.
My earliest attempts at plug-in making related to EV:C, specifically to the planets Quake and Opal. They caught my attention because in all of Classic, you never see any two planets so close together. They were, IIRC, closer to each other than Earth and Luna; having two Planet's at that distance was unique. I wound up altering both planets, making Quake habitable, making both tech level 5 with some special tech levels set, adding a third planet and putting them all under a new government...
However, at the time I was simply altering the data file. One day, James wanted to play EV without my changes, and... Let's just say I wasn't in the habit of making backup copies yet.
I'm amazed I still remembered that. I must have been 10 or 11 at the time.
After that, I got into using the plug-in system. "EV Tuner" was still relatively new, and I didn't quite trust it yet (... That must make me sound so-o-o old...).
I remember using Mechanisto to try and render ships back then. My very first ship was supposed to be a Confed planet-killer. It was larger than any other ship in the game, and I can remember thinking that a half-hour to render a ship was too long; I avoided doing anything that big again. It looked like a large, long cylinder with four other cylinders attached by rectangular, backward-swept columns.
My second ship was something I called a "Confed Attack Fighter." It was as fast as an alien fighter, and had a non fuel-eating "Proton Beam Cannon" as it's weapon. I had wanted it to look something like a jet fighter, and I redid it four times before I was satisfied; remember I had wanted it to be special, the best of my work. Looking back now, I can't help thinking... how Frikkin' Ugly it is compared to what I can do today!
Much of the rest of my work from that time was uninspired, and I drifted away from developing after EV:O came out; For whatever reason, it just didn't inspire me. I was lured back by Nova though, and I'm playing around with what I can do with it; we registered it the day we downloaded it, within two weeks of when it came out ("We" being myself and my older brother James Chin from the Banter and Brawl).
After I had played through the major story lines, I fired up Mechanisto again and started working. Some of the first things I did for Nova with Mechanisto were remakes of the Hawk and the Alien Fighter from EVC, and a cross between the Cantharan Schooner and Cruiser from Ares. This was mostly for practice, and to brush up on what I knew about Mechanisto.
For a free product, Mechanisto has done a lot of good for me, but I think my imagination is beginning to exceed its limitations. I've lost four ships because, either they or their scenes, were so complicated that Mechanisto didn't save properly, and corrupted the files. With one, there were too many (Four+) light-sources for it to save properly; for another too many moving parts; for the rest... I'm just not sure.
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"... Look, I designed the Cloak-Hunting Missile. I know everything there is to know about it, so I know exactly what I'm doing..."
"MISSILE SELF-DESTRUCT ACTIVATED: 5... 4... 3..."
"... Of course, I could be wrong..." - Me.