https://steamuserimages-a.akamaihd.net/ugc/38946276534474334/9DACEFF3651C06FAD8E845B0B5E8E0C2873CF59F/
You *can* receive free booster packs randomly, but I believe the eligibility is the same as free card drops, notice how the only f2p game on the list is awesomenauts and that's because I got it back when it was a paid game

also I mentioned the mini QA next to the card drop counter, here's the fullpage FAQ:
https://steamproxy.net/tradingcards/faq

https://steamuserimages-a.akamaihd.net/ugc/38946276534447964/D1A005109C62652EF0CFA9DF1ECFA38C10B78CF5/
Oh, you're creating boosterpacks from gems, I didn't recognize that page because I never use booster packs

You aren't being gifted cards; you're paying gems to create a pack of cards and the gems number is the cost - not the value - of the pack in question. You can also use steam points to buy badge rewards (emotes, wallpapers, etc) directly and steam lets you do this on games you aren't eligible to receive free cards from because you're paying for it, not receiving it for free.

I've never played this game, so never spent a cent and yet I can create a booster pack... Just to confirm what I already "knew".

https://steamproxy.net/app/442080/discussions/0/360671352682203120/
If you got cards w/o paying they must be doing something funky on their end then, card drops for freemium players in f2p games isn't standard

https://prnt.sc/Eio7uKCO2p4k

Ah thank u, I didn't know :D But before announcing something, check first..