Here are some of the platforms we directly integrate with:
Payment Processors:

TSYS

Heartland

Amazon Pay

PayPal Payments Pro

Square

Authorize.Net
eCommerce Related:

MaxMind

TaxJar

SmartyStreets

AfterShip

Retail Management Hero (RMH)

Google Merchant Center

Facebook Pixel

Slack

Swipe It
E-Mail Providers:

MailChimp

MailGun
3PL's (Third-party logistics):

ShipStation

ShippingEasy

ShipWorks

Easyship

FedEx

UPS Shipping

UPS® eFulfillment

Shopify

Ruby Has
CRM's:

Zoho

Improveit360
Misc:

Hatch

Google Maps Api Keys

Firebase

Crisp

UserWay

Yext Knowledge Network

LiveChat

Elfsight

Mindbody

ShareThis
Import Capabilities:

WordPress

Joomla

BigCommerce

Shopify

Squarespace

Magento

OpenCart

Microsoft SQL Server

WooCommerce