Or pick a size, then select a part for its color and brightness at a certain current.
These are all 0805 size LEDs for example:
http://www.digikey.com/product-search/en/optoelectronics/led-indication-discrete/524729?k=led&k=&pkeyword=led&pv16=6&FV=fff40008%2Cfff801b9&mnonly=0&newproducts=0&ColumnSort=0&page=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25