I love all of the ones you just mentioned! (Except for Love Little Thieves, which I haven't tried.) Cinders and Cyanide Tea especially! Taarradhin is definitely their best as far as story and quality, but Nachtigal's sort of my favorite for shallow-ish reasons (Luca and it was my first of theirs.)
This is a demo of a great game: Seven Kingdoms
The descriptions in the link but basically it's this game really heavily involved with intrigue and politics and much better than I thought it would be. I thought that "courtship" would be central, but tbh it's easy to forget about the matchmaking with all of the content. The characters are so much fun to interact with. Tons of romance options and two hidden options! There are stats that track rivalry, respect, friendship, and romance. I can't endorse this one enough. It's the release I'm looking forward to the most.
There's also Lucky Rabbit Reflex. A complete, commercial game with a free demo. You've probably already played it, but it's really great and addictive. It's a stats raiser, though and idk, that might not be your thing.
Essence! After Seven Kingdoms, it's the game I'm looking forward to the most. Although, I think this'll be free when it's done (Seven Kingdoms will be commercial.) It's post-apocalyptic with a really likeable and I think unique protagonist named Alice. She's a robot with a human soul and her hair is amazing! The side characters are funny and engaging. The creator of Essence is also really receptive to feedback and good about replying to comments (as far as I've seen).
Oh and Ascension: Echoes in the dark is a free game with a character whose appearance can be customized. You can choose races. It's not finished yet, but the demo has been released. And it's great. It's been influenced by Dragon Age and it shows. There's even some hints of exploration where you can wander around and interact with NPCs. And it's free.
And I guess lastly for me would be Magical Diary which is a magic school game so yay! I'd probably like this more if you could choose which Hall you lived in but you can customize your characters looks! So big yay there. It was the first VN I ever played so maybe my opinion's colored (I remember liking it but being weirded out by the focus on dating; I still kinda am by some VNs). Also it may have given me too high expectations of diversity in casts (so surprised by all the VNs that are just white guys as options, that I've seen at least). It's also on Steam, which can be cheaper if it's on sale.
I can't believe I almost forgot A Troll's Fairy Tale. Awesome story, awesome protagonist. There are I think three routes, but I've only seen the two good ones. And those two are very, very good. Routes are pretty linear but eh, it's very story focused. Super enjoyable and free.
(Sorry for the long response)
You can find a lot of WIP otomes on Lemmasoft forums. They're not all otomes, but most will have GxB, BxB, GxG, etc in their title so you know who the protagonist is. Also, most are free.