If you can;t find what you want then theres no harm in gathering ideas from different cakes and also drawing out how you will like it to be (you don;t have to be an artist!).
Whoever is making your cake should understand your vision, and better yet add ideas to create a cake for YOU to create something unique.
As you would with a florist go along and have a chat with your cake maker... You'll come away with a clearer idea of what you want.
Im lucky in this department, as like you im so indecisive to the point I get upset and stressed about it (not you me) so where the cake is concerned I showed my Mum a few ideas and have left it as a surprise for our wedding day and for once I actually feel excited and comfortable with not having to stress about it, im not saying have it as a surprise just saying there are ways to remove the stress of indecisivness
xx