Polish Molish Meadow is one I'm likely to wear during spring, a light green base with other green glitters. Also Barry M Pistachio is one for spring, its a light green, plain cream polish.
I think Orly Plastic Jungle would be a good polish for St. Patrick's Day although it is hard to photograph accurately. Fancy Gloss Rust Shards is a good gold looking flakie which I will be wearing over 17th March.
Best polish that can also be worn as a topper, for this prompt I think Lumen Crystal Cave it can be worn as is but also as a topper which is how I prefer it.