https://www.comc.com/Cards,sc,=2011+...update,ot,i100
Most Topps cards made today have multiple parallels. They have the base flagship cards (nicknamed "paper" since they're not chrome) and then the chrome, refractor (rainbow effect tilted in light), and then multiple colored refractors.
For 2016 Bowman Draft, here is the list:
Parallels
All 200 base cards are available in the following parallels.
Silver (/499)
Blue (/150)
Green (/99)
Gold (/50)
Orange (serial-numbered to 25 copies)
Red (serial-numbered to five)
Black (one-of-one)
Chrome
As usual, the entire 200 card base set is also available in a Chrome version, which is also available in the following Refractor parallels.
Refractor
Sky Blue Refractor
Purple Refractor (/250)
Blue Refractor (/150)
Green Refractor (/99)
Gold Refractor (/50)
Orange Refractor (serial-numbered to 25 copies)
Red Refractor (serial-numbered to five)
SuperFractor (one-of-one)
http://www.baseballcardpedia.com/ind...raft#Parallels
If you collect every refractor version of a single card, you have "completed the rainbow". I got a red refractor of 2015 bowman draft prospect Jordy Lara and I currently have like 20 versions of the same card. Missing the two 1/1s (superfractor and metallic paper), and a 1/5 red paper.
To make it even more confusing/difficult, some of the parallels are only released in Japan.