What are the best training packs?

I have over 200k training, which training packs have the best odds? Or is it just random.

its random and no luck. ive ripped back to back 94+ training packs and ive always got the lowest 94 for resell. did this with 4 different promos and never got anything good just sold

There isn't one with better odds. Your best bet is to look through each of the active promos and look for the one with the most expensive LTDs as well as random champion cards that go for a lot and rip those. 

For example, right now on Playstation, the new Polar Vortex WR is currently selling for 400k while the Center and a few other random cards are going for close to 300k. Obviously you could rip all 200k training and pull the cheapest cards out of all of them, but you at least have a chance to get lucky and hit an LTD or one of the expensive champs.