Card draw
Card draw is a simple mechanic, if the card you play meets the conditions, you draw a card from your remaining deck to your hand.
You got 6 cards of the game start. This is 25% of the 24 cards you can use with 3 axies.
The chances of which axie has a card or which card is random. The limit is 2 cards per type, 8 cards per axie. If you don't use your cards you will need to discard some of them until you get less. If you don't use energy, you also waste one if you end with 9 or more energy since you would get 2 back.
You draw 3 cards per turn, so in total 6-9-12-15-18-21-24 by turn 6. Itcannot repeat until turn 7 or until one of your axies die, there is no round limit for this, only that each card you use goes into discard pile, when you use up or discard all cards your deck is reshuffled and starts again. This means if your opponent used up 2 of the same cards, he won't be able to draw them anymore, and usually this means the end of that card until an axie dies.
There are only 6 cards that draw a card:
As you can see 4 of them are on the back, 2 on tail. Hare is a beast card and beasts aren't the fastest, so the effect won't usually trigger, but if the opponent doesn't play a card, and you don't use your bird, it happens.
Cattail is not the best plant tail, but it's free and has some chip damage, carrot will use one and only gets it back if attacked and if the shield breaks.
Blue moon is also very high damage card and higher armor than the other aqua back cards, also ranged card so won't be blocked by gravel ant. The effect is not good, last stand rarely occurs, and mainly with beast, bug or plant is more common. Stopping it with shoal star or ending with oranda is much better choice. Or any multi hit small damage.
Hero is also free but only occurs when hitting the Aqua/Bird/Dawn category and all of them are faster than a beast so in direct combat it hardly helps, mostly good for a bird or aqua to recycle cards.
Pumpkin is the highest shield plant card, and 3nd highest overall (red ear for reptiles, and hermit for aquas) . The weakness of shields is that they only last a turn, so if the opponent won't attack into it they got no value. This is why the card draw is a slight recompensation for it.
Finally bonesail is a good value card with card draw and a high average shield and damage, ideal midline bruiser card.
Focusing on card draw doesn't seem to be that important, as none of them are good enough just for the effect of card draw but is certainly useful to have some. mainly useful if you got energy gaining cards, or zero cost cards, as you might need to have more choices to produce high enough damage. In future if they change or introduce cards that draw more than one card or they are free and easy to reach conditions, then it can be a mechanic that controls the meta.
Since you start on 3 energy and 6 cards then gain 2 energy and 3 cards, usually you got 3 choices first turn and 1 each additional turns if you assume each card cost 1. This also means that by turn 3 you have to spend something or you might get discarded. But overall in 6 turns you draw all 24 cards and you can only spend 15 energy on them. So you got 9 cards extra that you either cannot spend and get discarded, or you can gain more energy to spend more, or zero cost cards, or flex them to have cards that are good in certain conditions only.
In standard front to back (no backdoors, each team attacks front tank, mid then backline) this would be 66% for plants and 33% for midline.
Backline usually needs high damage cards or 1v1 potential.
As for discarding, there are only 2 bug cards, discard really depends on luck, can be good early and loses value in 1 v 1 as they get the same card back at the end, it's random so you might not get any valuable card out, but most teams got only useful cards so the more complex and synergistic a deck is the more it suffers to discards(like antenna chains or lunges, cute bunny, ronin imp, other combos).
The combination of the two can make the opponent lose up to 4 cards so you can disrupt their combos or strip them from damage cards and reduce their choices, this also means that if they try to use the cards early and not lose them, you gain more value out of your shields and they might lose combo damage.
Since both cards are above average for a zero and one cost card, it can be really powerful, but probably not on a bug, but on a reptile or dusk. 2 pairs of 4 would be disgusting as the opponent could lose 8 cards to it, especially for 2 v 2 where they only have 16. 3 pairs would be 12 discard which is a bit overkill and probably expensive, I haven't seen any game like that but it would be really crazy.
The cards aren't lost forever, they come back, and that can be also bad, as you might increase the odds of pulling a 3rd ronin or something. But with cards like serious, that are kind of weak without the condition, returning them is not bad.
Card drawing rules are useful to know in pvp, if he used both "Serious" he won't be able to destroy your energy, or two of the "pumpkin", he can't raise a shield.
Also good to check how many stuns he has, a normal terminator has 2 chomps and 2 snail shells. This also means he can stun you 2x in defense and 2 times in offense, so you need to waste a card to remove the effect, you will need 4 cheaper cards to go to waste for this.
A RIMP beast (ronin-imp plus 2 nut cards usually) most often uses a 4 card combo same time, to gain maximum crit, energy and kill a plant in a single turn.
This means he can only use the full combo twice before his tank dies. If an axie dies, all his cards are removed from the deck, even if you got the same card on another axie, you cannot use it with other axie, they belong to a certain axie. So if you or/and your opponent have 2 axies, the deck is only 16 cards.
You still get 2 energy and 3 cards, but you already used up some, a plant tank on maximum 6 parts plant has 516 health and two times 130 shield.
This usually means you need 5-8 high damage cards to kill it or some crits and class advantage/card advantage. So a 16 card deck in 2v2 usually takes 3-4 more turns at maximum. When the 2nd axie dies, the reshuffling might occur each turn.
As you hold up to 8 cards, the ones you use up will come back to your hand. Some meta axies use this strategy to chain the same combo each turn and win the game by outlasting you. One example is Leafbug (0 cost energy gain) tanks on backline with hotbutt/grass snake/yam (poison or disable), zigzag(heals them and damages you) and pumpkin for shield. This allows them to play 4 cards with 3 energy and gain 1 energy each turn.
People count energy but you can also count cards. The number on the top right is their cards number on the previous turn, they get 3 more. Normally 1 card=1 energy, but you got to track their 0 cost cards and energy gains, to be sure. When you use serious or other steal cards and you don't gain energy, you can restart counting their energy from zero. That's why is useful to check all opponent axies at start to see if they got any energy, draw, discard mechanics or any zero cost cards.
In the first Yu-gi-oh game they underestimated how strong pot of greed is for drawing 3 cards, it was one of the first nerfs. In hearthstone a card draw effect is valued for 2 mana which is a low cost card, but considering that most decks rarely ever used anything above 6 cos, that was a pretty surprising fact for most people. Most deck building rules were to include 3-4 card draws but some of them were only card draw, this thins your deck to find combos faster. The most famous card draw based deck was miracle rogue which used cheap spells to get trough the deck and provide insane tempo wins. Since most decks were powerful with 3-4 cost cards, and the energy went up from 1 to 10, the average was usually 3 energy, so if a single draw worth half value of an average card cost, in axie infinity most zero costs (20-80) not worth more than third of the damage of cards (110-140), so card draw might be a powerful effect.
