For some reason I LOVE pansies and violets. I think pansies might be because their hybrid have a very different vibe than the regular ones, and there isn't some of them there look bad!
But I don't like tullips ._. Especially NOT the whites since they are trying to take over my town....
Adding to my earlier post, how good a flower looks is usually different depending on your town and/or its theme.
If it's fairy-pastel-food-cutesy or modern/city-like, roses and pansies are your obvious choice. Carnations seem best in more developed towns as well.
In foresty/nature towns, tulips and cosmos work out well.
In Zen/Japanese/sakura towns, lilies and violets look good, though tbh lilies and violets work just about anywhere.
Jacob's Ladders can also go anywhere, though imo they don't do as well in fairytale towns as in other themes.
Aaaand if you want rafflesias, I mean you can GO for that look, no one is stopping you.