I think Rainbow, Fire Queen, Miracle, Dark Matter, Paradox, Obliterator, Decay, and Scorpio are the worst. Reasons:
Rainbow - type of deck, and fairly unfitting IMO
Fire Queen - Has a card similar to it's name in it's deck
Miracle - IS the name of a card. Enough said
Dark Matter - A deck with light should not be named Dark
Paradox - An ability, and doesn't have said ability's element
Obilterator - Sounds like it should be announced over a loud speaker at a monster truck rally*
Decay - Has nothing that fits the name, except maybe decaying your quanta
Scorpio - Great name, but if the scorpions come out, it becomes meh
*I would have quoted, but it screws up my formatting. Original line belongs to smuglaspeEDIT: In other words, I agree with everyone.
![Tongue :P](https://elementscommunity.org/forum/Smileys/solosmileys/tongue.gif)