Some notable other APIs useful for digital marketing are described below:

Search Console

Get your SEO keywords back after (not provided) via Google’s Search Console.

## This installs searchConsoleR if you haven't got it already
if(!require(searchConsoleR)) install.packages("searchConsoleR")
library(searchConsoleR)

## authentication similar to googleAnalyticsR
scr_auth()

seo_data <- search_analytics("your-website.com", dimensions = c("date","query"))

BigQuery

This is useful if you have Google Analytics data going into BigQuery from Google Analytics 360, as well as if you’re using BigQuery with any other data. See BigQuery section of googleAnalyticsR.

## This installs bigQueryR if you haven't got it already
if(!require(bigQueryR)) install.packages("bigQueryR")

library(googleAnalyticsR)

## Authentication similar to googleAnalyticsR
bqr_auth()

## This function turns GA dimensions/metrics into BigQuery SQL

bq <- google_analytics_bq("project-id", "dataset-id-ga-viewid", 
                           start = "2016-01-01", end = "2016-02-01", 
                           metrics = "users", 
                           dimensions = c("source","medium"))
head(bq)
             source   medium  users
1   mavas|blahbs.ru  display  47837
2          examp.ae referral   6090
3   lm.facebook.com referral    335
4       ghtie_yahoo  display 133900
5      fjsfs_inmobi  display  19887
6 tripadvisor.co.dk referral    307 

For more general BigQuery extracts, it may be better to use the more developed bigrquery() package instead.

Twitter

Historically, the go-to package for getting Twitter data using R was twitteR. But, the authors of that package have recently released a new package called rtweet, which, along with being much easier to search Google for help with, offers quicker authentication options.

Facebook

Rfacebook offers Facebook user data, and fbRads gets you connected to the Facebook Marketing API.

Make Your Own

If you can’t find an R library, then you can make your own. httr is what most of the packages are built on and comes with a quickstart guide.