There are many payment gateways available for websites to use. Some of the most popular payment gateways include:

1. PayPal: PayPal is one of the largest online payment systems and is widely used in ecommerce. It allows customers to make payments using a credit card or bank account, and it provides merchants with tools to manage and process payments.
2. Stripe: Stripe is a payment processing platform that provides merchants with tools to accept payments from customers using a variety of payment methods, including credit and debit cards, as well as mobile wallets like Apple Pay and Google Pay.
3. Authorize.net: Authorize.net is a payment gateway that provides merchants with the ability to accept credit and debit card payments, as well as electronic check payments, from their customers.
4. Square: Square is a payment processing company that provides merchants with tools to accept payments from customers using credit and debit cards, as well as mobile wallets like Apple Pay and Google Pay.
5. Braintree: Braintree is a payment gateway that provides merchants with tools to accept payments from customers using a variety of payment methods, including credit and debit cards, PayPal, and mobile wallets like Apple Pay and Google Pay.
6. Amazon Pay: Amazon Pay is a payment solution provided by Amazon that allows customers to make payments using the information already stored in their Amazon account.
7. Adyen: Adyen is a payment processing platform that provides merchants with tools to accept payments from customers using a variety of payment methods, including credit and debit cards, mobile wallets, and bank transfers.

These are just a few of the many payment gateways available for websites to use. The payment gateway that is right for a particular website will depend on factors such as the type of products or services being sold, the target customer demographic, and the website’s specific needs and preferences.