Here I've compared the first design of each OC with their current design, and to scale. I figured I should do something like this, seeing as it's been about 4 years since I created my first Pokemon OC. I would have included Chalky, but really, he hasn't changed much except for his wardrobe. Please note that the “old” OC designs may not be 100% accurate; I did them mostly from memory, and I have little to no way of looking at any references for Sparxx/ZapTail and Gem's first designs.
SPARXX/ZAPTAIL So many changes in design over the years, yet still sooooo much of a horribly underdeveloped Gary Stu with no personality whatsoever. I would have drawn the Pikachu version of Sparxx, but really, he wasn't a Pikachu for very long, and in every version of the story, he evolves along the way.
GEM I could go on for hours about all the changes I've made to Gem. Little-known fact: Originally, he was just supposed to be a supporting character for Klaww, who was to be the main character. Now, Gem's supporting characters have supporting characters. I'll mention him again when I talk about Bloodstone.
DRIKA Drika really hasn't changed so much, aside from being upgraded to the main character if I ever redo the story with the Shadow Pokemon OCs. I just haven't been feeling it lately.
BLOODSTONE Oh Arceus, the changes. Changes up the butt and out the nose. Originally, I was going to make an “evil” antagonist for Gem (hence why I gave Bloodstone such a badass name), but then I decided, “Nah. I'm just gonna make him kinduva jerk. And have them be related.” In the beginning, Bloodstone wasn't even really meant to undergo any character development. His design didn't even include any noticeable attractiveness (believe it or not, yes, there was a time when Bloodstone didn't have dat ass). He was just an asshole, plain and simple. Now, though, he's become a perfect example of the sad fact that being good-looking and having fame and money don't make you as happy as meaningful relationships, which he can pretty much no longer achieve because of the choices he's made and the lifestyle he lives. The tragedy is, Gem has what Bloodstone wants and Bloodstone has what Gem wanted. And there's little to nothing Bloodstone can do to change his situation. You can't just quit being famous.
HOODIE He's pretty much stayed just about the same except for his design/backstory, and becoming quite poular among the “non-dA” watchers. My Arceus, he looks totally different than what I started with.
CUTLASS Is it odd that her character and design have stayed nearly the exact same even though her backstory and history are only about half the same? I find it odd. Really, though, the biggest change I've made to her was Damascus, if that makes any sense. I like to compare her to Gem a lot, hence why they're so similar in many aspects. They're both motivated to achieve more physical strength due to underappreciation by their peers, they're both easily insulted (though Cutlass is much more so than Gem), and yet, they have entirely different relationships with their brothers. Maybe that's the reason Cutlass is getting so popular lately, though: She's a lot like Gem.