WhatsApp has its own emoji designs which are displayed on all WhatsApp platforms (except WhatsApp for iOS, which uses Apple's native emoji set).
Prior to WhatsApp having its own emojis, Apple emoji images were used by WhatsApp on all platforms including Android and the web. In October 2017 WhatsApp released its own emoji set and ceased using Apple emojis on any non-Apple platform.
One emoji supported by WhatsApp but no other platform is the Texas flag emoji. This is a valid subdivision flag supported by Unicode, but not listed within any Unicode emoji release and as of 2018 is not supported by any other major vendor.
Emojis from WhatsApp 2.17 are displayed below.