If you look the bottom right of a credit card you will see what is the payment gateway for that card.
These gateways are what facilitate the payment process for your cards. Do note, that the credit is provided by the issuing bank and not the payment gateway. However, the banks pay a fee for using the gateways.
In most cases, for choosing a credit card you need to judge based on the offers on the card being provided by the Bank. However, each gateway also provides additional offers to promote the use of their gateway.
I think most of us have no idea about these offers mostly because they are not the hottest of offers, but could be applicable is some cases and are worth knowing.
For card collectors such as you, it would be delightful to know that in many of these gateways there is a tier of options and the offers get better with each higher tier.
VISA
This is the most widely used gateway by credit card issuers.
Visa cards come in the following versions. They are shown in ascending order of privileges. A few of the notable cards are listed.
Visa Classic
Visa Gold
Visa Platinum
Visa Signature: SBI Prime, IDFC First Select, MMT ICICI, Indusind Legend
Visa Infinite: SC ultimate, HDFC Infinia, Citi Prestige


All image source is the visa website
Visa Classic, Gold and Platinum come with no notable features.
However, all the cards do come with the merchant offers. The link is given below.
https://www.visa.co.in/pay-with-visa/find-a-card/credit-cards.html
A snip of a few of the offers are

I remember that Visa Signature provided 50% off movie tickets (Upto Rs 300) offer on Bookmyshow. Visa Infinite provided the same but was inclusive on all booking types including events.
I know this doesn't mean much but when you use Visa cards for complementary airport lounge access you are charges Rs 2 while Mastercard charges you Rs 25 for each visit :)
Mastercard
This is the second highest issuer in the world. The tier of master card are given below:
Standard mastercard (includes Gold)
World mastercard: Yes First Preferred, SBI Elite, RBL world Safari
World Elite mastercard: Yes Private
Mastercard has a running offer called priceless wherein you get access to shows, experiences etc.
For Indian master cards you can see the offers here by selecting your credit card.
https://specials.priceless.com/en-in/homepage
A snip of the offers is below

Rupay
Our Very Own Rupay card comes in the following flavours
Classic
Platinum: SBI Shaurya,
Select: SBI Shaurya Select
The only notable difference between them is Classic and Platinum come with Personal Accident Insurance cover upto Rs.2 Lakhs whereas the Select version comes with Rs 10 lac cover for the same.
The link to the merchant offers is
https://www.rupay.co.in/rupay-offers
A snip of the merchant offers

Diners club
Diners club credit cards are currently only issued by HDFC in India.
They come with the following benefits two additional benefits.
1) Dining

2) 10X accelerated reward points with partner merchants

American Express
American Express themselves also issue cards and they also issue cards from other banks.
The best advantage of holding amex cards is the amazing offers that come from time to time.
You need to enrol for these by logging in your American express account.
It has additional merchant offers. Link is below.
A snip of the present merchant offers is below
