Here are the most useful cards in all the series up to date:
10. Trunks Energy Sphere
    The only  card like it.  This is the only card that can counter pesky Stare Down's, Saiyan Truce Cards, and Time is a Warrior's Tool.
9. Cell's Threatening Position
    Well, the ultimate anger counter card has some disadvantages to it that gave it number 9 slot.  I can be countered with Trunks Energy Sphere, and it's not a noncombat card, which if you draw it at the wrong time it won't be so effective.
8. Straining Jump Kick Move
The Underated Straining Move card is a very good, often overlooked card.  It's the best way to get around pesky powrs and discard all of your opponents drills.  It's a great attack in it's own right.  And you can use it with Winter Countryside to use it mainly as an attack.
7. Blue Terror
     Searching is great nowadays and this is the best one.  Search for that needed card, what else do you need?
6. Black Searching Technique
    Very awesome.  Take 2 pesky cards out of your opponents deck and take a good long look at it.
5. Expectant Trunks
    Defiantly an evil card.  You can recylce Time is a Warrior's Tool over and over again with this.  YOu can even combine this Trunks Sword Position 3 to recycle it more.
4. Chiaotzu's Psychic Halt
    Now, I no your yelling at me for this but it's true.  There are better cards actually.  This is high targeted card and has a good chance of being discarded by an attack.  Plus it's remove the game.
3. Where's there's life there is Hope
    I tried to resist using URs, but I coldn't help it.  It pretty much speaks for it selfTime is a Warrior's Tool
    I prefer this to Halt.  Basically Becaus you recycle it with Expectant Trunks, Trunks Sword Position 3, etc
2. Time is a Warrior's Tool
     I prefer this to halt.  It can be TES but still, you can recycle it and reuse it again and again.
1. Saiyan Truce Card
    My favorite card.  I always get a smirk on my face when I draw this.  This card is pure evil.  You better run 3 TES just to counter tis cuz you'll get a slapping if you don't.  Espically if they play Battle Pausing, Time, EDB3, etc.  You literally deal life cards of damage to them.  This beats every card by itself.  They draw a huge hand and you have no attacks or defense, this will save you.  It beats Halt, which many consider the best.  This card is good in any deck.  You get to stack up your hand and smash them with double the cards.
Thanks for looking!