I don't remember what all you get with default but here are some cards you probably want for every strat:
5x Nazrin
5x Shizuha
5x Luna Child (stupidly good waveclear no matter what)
1x Minoriko
4x Gohei
1x Reisen 1x sakuya (crowd control, sakuya's cooldown reset can be set to ALWAYS reset one ability if you turn off her AI, use your main tower's abiilty and then use the reset on that tower, then turn AI back on)
1x formal dress that gives you gold (DOESN'T need to be in your inventory, it passively gives you gold even if it's on the ground)
1x SR EXP amulet (forget what it's called but it's great)
1x consecrate box
4x electric karyogamy stick (especially for Ran, if you want to use her as your primary slower) (remember, slows don't really stack all that well so only go for one, like Murasa with 4x moon rabbit blades in a pure damage strat or Ran in any strat)
1x Kanako (SSR, stupidly good CC ability at 1*)
Reimu is usually always useful either in pure damage strats or for stupidly good CC, but please do not use more than 1 of her if you're in a game with others because she destroys the servers
however many Bomb consumables you have leftover in space in a deck


after that just go for whatever's good for the strategy you want to do
like, for a pure damage strat, you'd want 2x rumia, 4x yin yang tax payment orbs, 2x kaguya and 4x SSR camera and whatever supporting towers/extra damage towers (or both, in the case of Reimu) you'd want for that

always remember, items make a world of difference and generaly it's better to have at most like 5 towers dedicated to dealing damage and 7 really good CC/buffing/debuffing towers than it is to have 10 damage towers with shoddy item builds and no support, ESPECIALLY if you can't get all fo them to 5* and if you're running physical or magical damage, since enemies get tons of armor/MR in endless waves

thanks you I was wondering when I played with my friends why sometimes it was so laggy. so it was reimu

Don't put 2 rumias in your deck, she immediately gets the full skill ups if she is awakened, and you can't have more than 1 awakened rumia. So 1 rumia is enough.

Originally posted by ajo1k:

Don't put 2 rumias in your deck, she immediately gets the full skill ups if she is awakened, and you can't have more than 1 awakened rumia. So 1 rumia is enough.

Huh, didn't know. Neat.