The new update to Google Keyboard which has essentially changed the name of the app to Gboard, makes it possible for Android devices that are running on versions of the operating system below Android 7.1 Nougat to access the GIFs in the keyboard. This particular feature was initially only available to devices running on Android 7.1 Nougat, and the new update to Gboard which recently went out earlier this afternoon makes it so that older versions of Android can enjoy the easy access to GIF images right from the keyboard too, which of course makes it much easier to find the GIF image you want, and a lot easier, as well as faster, to share them with friends and family.
That being said, if you've already updated to the latest version of Gboard which is just Google Keyboard 6.0, then you may have noticed that the GIF support in the keyboard does not show up in all of your apps. This is because even though the feature now supports older versions of Android, it still only works in a few different apps, including apps like Google's Hangouts, Allo, and Messenger. Beyond these apps, you might find it difficult to stumble upon another app that supports the feature. Of course, if you really want the access to GIFs from the keyboard no matter the app, there is always the option of checking out other keyboard apps to see if any support this kind of functionality.
For example, if you want GIF access from the keyboard in all of your apps, you could opt to give the Fleksy (beta) version a try which includes GIF images in their keyboard, but the only downside is that Fleksy will no longer be updating the app as they announced earlier this year. That being said, it is a workaround to only having quick access to GIFs in just a few messaging apps, which may be exactly what you're looking for. As time goes on, Google may also choose to include support for Gboard to offer up GIFs from more apps, but for now there is a bit of a limitation.