So far I'm really liking Slipstream from Cyberverse. Though I have yet to finish the show, so I'll have to get back to this vote another time. ^^;

 

Just saying don’t get too attached

 

Oh I knew beforehand. Hasn't happened yet, but I'm still curious about how it goes down. As well as the consequences.

 

I gave it to Thunderblast. Not the most PC friendly example, but nostalgia won out, as well as the rarity of aquatic Transformers. Slipstream would be my alternate.

 

BW Blackarachnia would normally get my vote, but she's not technically a Decepticon; she's a Predacon. She also switches sides in the third season of Beast Wars and is actually a Maximal for the entirety of Beast Machines, so even if "Decepticon" really means "female Cybertronian antagonist" she might not fully apply.

Strika is great (I especially appreciate her unusual design), but I don't feel like she's ever gotten adequate time to really shine (being introduced as late into Beast Machines as she was and being more of a background role in Animated and Cyberverse).

I have a soft spot for Animated Blackarachnia (I really liked her as a kid), but I acknowledge that her relationship with Optimus is perhaps a bit cliche.

I like what I've seen of Slipstream and Clobber in Cyberverse. Shadow Striker also seems like a cool concept. I liked Slipstream in Animated as well, but she wasn't as fleshed out there as she was in Cyberverse.

Thunderblast is a lot of fun to watch.

Lady Mega is surprisingly complex antagonist, and she gets much more screen time than most other female antagonists in the franchise. She'd probably be my number one pick if she was Cybertronian rather than human.

They don't show up much, and they're kind of silly, but I have a soft spot for Lyzack, Leozack's twin sister, and Esmeral, the Decepticon Empress of Destruction (Deathsaurus' wife). They just have neat designs.

Scylla (from Beast Wars II) is amusing, but she's not a proper Decepticon (or, for that matter, a proper Predacon).

Trickdiamond is pretty cool. A female Swindle is a great idea, and she seems to be the most interesting member of the Megatronia combiner.

I guess what I'm saying is...I like them all. However, my favorite female Decepticon would have to be Shatter, the main antagonist of the Bumblebee movie. She was smart, she was scary, and she was largely without sympathetic or comedic traits, something unusual for female Decepticons (and antagonists in general). What's more, I really liked her design. She's just awesome all around.

 

Starscream

 

also, RotF Alice

 

Blackarachnia. I more or less mean BW Blackarachnia, since that's the version I prefer, but I understand Predacon does not equal Decepticon. The answer would still probably be Animated Blackarachnia for me though. An actual serviceable backstory, character motivation, and genuinely interested and complicated dynamic with the heroes is something you don't see in many villains in this franchise, shockingly.

After Blackarachnia it would probably be Airachnid for me, and that's not just to be contrarian, that has more to do with a lot of villainesses in Transformers being poorly developed. I'd pick Strika if it boiled only down to design and concept, but after re-watching Beast Machines, despite proving to be a huge threat in her first episode she's introduced, she's kind of overshadowed by Obsidian in a lot of ways and doesn't actually do that much given the few episodes made of her. Airachnid actually did a lot. She's not the greatest character or anything, but with Prime's plot and characters in mind, she's not nearly much worse off than a lot of the other villains in that show. I'd rate her under Starscream and Knock Out in terms of consistency, but probably above Soundwave, Breakdown, Dreadwing, or Megatron in terms of being a dynamic villain that actually went lengths to generate conflict through her motivations. How these conflicts resolved is another story, but it's more than can be said about characters like Slipstream or Shadow Striker, who barely developed beyond their initial concepts in each of their appearances.

EDIT: How did I forget Shatter and Clobber? I actually really liked both of these characters as well. I was disappointed that Clobber's character reached a peak at the beginning of season 3 and then turned to becoming an Autobot since I guess that's the path the writers set for her, whereas Shatter is similar to Strika to me, in that she should definitely receive more development in a future series. The animators in Bumblebee clearly put so much work into her methodical fighting styles and body language, I would really like to see more of her in the future. I also forgot Strika isnt even technically a Decepticon outside of Animated and the new comics.