Our wedding colors are purple/lavender and yellow. My favorite color is purple and his is yellow so that was easy. White and/or silver will be the other color we use. It's hard to really find things for a wedding in either of these colors, yellow even more so than purple and so that's why a lot of this is going to be DIY.
So far, some of the things I've bought are:
6 yellow metal pails from the dollar spot at Target. I bought them but don't have any ideas for them yet but they were the right shade and were only a dollar so I figured I should buy them. I might wrap ribbon around them in either silver or purple in a few days and see how it looks.
12 yellow plastic picture frames. 4x6. I bought them from Target in packs of 4 about 2 years ago and they've been discontinued sadly. I bought them for this monthly photo thing I started with my fiance and I. But I'm going to use them for the wedding I think. Either as numbers for the tables or to label things on the tables, such as gifts and food. I figure it's a good way to bring more yellow into the wedding.
I have floating candles that are pearly white and flower shaped. I bought them at Hobby Lobby in packs of 6 for 9.99 but there was a sale for 50% off so I paid 4.99 each for the 2 packs I bought!
I also bought 36 packs of bubbles from Hobby Lobby. They're plastic tubes and the wand is white and has a heart at the top, the part you hold. I might figure out a way to decorate these. With ribbon around the plastic tube or hang something from the heart. Not sure yet.
I've also bought some glass candle holders from the Dollar Tree that are in the shape of a star.