Your comments
It's okay, I'll try to describe:
Every card has a
numer (#);
serie (don't know how they calls it exactly) (1st one was completed, now goes 2nd);
silver or gold border;
1st serie
black/white or black/pink back with "LIMITED RUN" logo;
plain silver or gold border;
no title of a game that goes on image.
$ maybe some other characteristics that I'm not found.

2nd serie
title of a game that goes on image;
foil silver or gold border;
colored back with "LIMITED RUN" logo;

1) 1 card adds to each order with game;
2) if you buy bundle you get a complete set of a cards of a game or games that comes in a bundle;
like these: https://limitedrungames.com/collections/everything-sold-out/products/super-meat-boy-fan-bundle
3) you can buy a limited run booster pack (when it's available for purchase);
4) if you buy a Blind box, you'll get a random game with random card.
The prices on Ebay are different - some card prices went to the moon, some cheap.
You can look for a deals by:
https://www.ebay.com/sch/1249/i.html?_from=R40&_nkw=lrg+card&LH_TitleDesc=0
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=limited+run+games+card&_sacat=0
There a couple of links of a unicorns:
I can also provide my excel table of a card.
The 1st serie content I've got at Reddit from Limited Run Games poll;
The 2nd serie I'm collecting b myself.
It looks like that:

Customer support service by UserEcho
Yeah, if someone interesting in collecting that cards and support this poll, that would be awesome!
More trustworthy data and analytics for people - the better.
I've found Pricecharting almost at start of collecting the games and it was very helpful to form an opinion about a deals.
Thanks for moving forward and make try