All
Probably the most risky trade rule, if you lose then you can wave goodbye to the whole hand you used. If you win, there are big rewards as you claim every card in your opponent's hand.

None
This option is not available on the Triple Triad game in FF8, but it is a regularly used rule at TripleTriad.com and TripleTriadX.com, being a safe option. You will not lose any cards from your hand, but you will not have the option of gaining any either. The purpose of the none rule is for trading cards for points, and where you do not want to risk your valuable cards.

Diff
Diff (or difference) is one of the slightly more complicated trade rules. If you win a game, the amount of cards you get is determined by the amount you won by. Therefore winning 8-2 is more desirable than winning 6-4 because you will gain more cards. Again, this rule also applies to losing, you will lose the amount of cards which you lost by.

Direct
This option is not yet available at TT.com or TTX, however we will mention it in case it is made available. The 'direct' trade rule means that you will keep whatever cards were your colour at the end of the game, regardless of whether you won or lost. Therefore, you should try to protect your valuable cards from being turned over so that you don't lose them, and in turn you should try to turn over your opponent's most valuable cards so that you will gain them, unless your opponent can turn them over again.
The use of this rule can encourage a very defensive style of play, especially where there are valuable cards at stake.