LSD would be alright.
It surprises me metoxetamine is useful since it bears resemblance to ketamine and I can have a hard time drawing on that, my skills are pretty much shot though on the other hand there is more interesting abstraction, I was reminded of alien symbols but also of a mentally impaired person drawing it :D good thing I finished it later.
4-HO-MET has given me the absolute most creative ideas, when I used it in a pretty high dose I saw and experienced great and otherworldly things, they were very visual as well. Even though you say that is not what you are looking for let me tell you it helped, because in visions I saw my own creative imagination at work and I came up with excellent ideas that I listed on a note and used later to inspire works that are still pretty much the nicest I have.
By the way one great thing about 4-HO-MET is that it stays light-hearted for much longer than mushrooms (which can be more serious to me), and it allowed me to focus on creative thought and not follow the guidance of the shroom so to speak. I can see 4-AcO-DMT being nice as well but it can be a little too otherworldly and I might have a harder time expressing the mindscapes experienced or visited on it. I guess you could say it's too deep and doesn't relate to everyday things well enough to be expressed in those terms.
Tryptamines are IMO your very best bet, they produce more conceptual distortions that let you tap into creativity - LSD has this as well, it depends whether you want to count it as a tryptamine.
I am not saying phenethylamines won't do you any good, probably most psychedelics will... but they remain more superficial for me and I can only work with things I am already seeing or thinking about so not too much novelty in comparison. 2C-E might get you there and 2C-T-7 and others also have potential but I feel like it would not be efficient.
The reason I am not more enthousiastic about LSD is probably because I have tried drawing under the influence multiple times and it always ends up a little too trippy. If I had used the method I used for 4-HO-MET and only written down the subjects to draw, enough to remember and visualize it all later on it would probably be a big success.
My recipe with 4-HO-MET was 20 mg, then a while into the plateau I took another 12 mg or so and quickly after that I also added the 8 mg I had left at the time. I guess when in doubt double the dose applied here. The trip kicked into full gear but it became pretty crazy though still manageable when I smoked some weed after that as well. Best recipe I can give you but less experienced trippers should definitely be more conservative with their tryptamine dose.