For ISO's to do anything you will want to change your iso set to and 8 iso set and equip iso's based on the set to get the bonus for your characters. CTP's are really hard to find. I have only tow or three of them and have been playing the game for a few years so don't worry about it. For comic cards all you want is scd and all attack and maybe dodge and crits.
Cards - There are 3 types of cards (IIRC), farmable cards (they are tied to a specific dimension rift), RNG reward cards (these have a chance of showing up in the LAB Shop, from high level dimension rifts as a bonus reward, World Boss Invasion, etc.) and Premium cards which can only be bought via various crystals, some legendary battle rewards, and I believe high level WBU chests.
Cards range from 1 to 6 stars. The more stars, the more stat options the card can have. The first two stat options are always fixed and colored orange. You'll find this applies to everything you see later on. Loki #17 as an example always has all attack/cooldown reduction for the first 2 stats. Premium cards have 3 stats that are "locked". Every other card has a set few options that can roll in a given slot (in blue). Using the Loki #17 card as an example, the 3rd "blue" stat can roll: Crit Damage, Mind Resist, Max HP, Ignore Defense, or Dodge. Ranking up a card (from 3 to 4*) may change ANY blue stats on the card.
The other modifier on a card is in a diamond on the card. This number ranges from 1 to 7 and determines the strength of the first two stats only. Generally speaking, ignore this number as the stats you roll are WAY more important than the rank of the card.
Finally, there are card sets. Once you 6* a card, it's locked in your collection (provided one exists, the angel rift's X-men card has no collection for example). When you complete a certain set of cards in a collection, you unlock a permanent stat bonus.
General strategy: You want to get 30% cooldown ASAP. Your next goal is 30% cooldown + ignore defense. Then add all-attack. Then physical/energy attack (etc.). To accomplish this, you want to start by rolling many 3* or 4* cards and equipping any card that has both Cooldown reduction and Ignore defense on it. Because blue stats may re-roll as something else, you pretty much never upgrade cards you've equipped to yourself. Instead, you'll overwrite them with better cards. From there, you try to start rolling cards with Cooldown reduction/Ignore Defense/all attack, and overriding a worse card. Continue doing this pretty much forever, because it takes a long ass time to get "decent" cards.
Loki's Ragnarok Uniform
Thor Ragnarok Uniform
Black Panther Uniform (3300 bundle)
all reward a premium card with Ignore Defense/Cooldown reduction and another attack stat. This means you're really only re-rolling for all-attack and it'll be your best card for a while.
I'll see about typing up ISO/Custom Gear later on if no one else jumps in.