COCA & COHA are two freely-available corpus of English, available though corpus.byu.edu It was developed by Mark Davies, Professor of Linguistics at Brigham Young University. The BYU Corpus is the most used online corpora, used by more than 130,000 distinct researchers, teachers, and students each month.
The Corpus of Contemporary American English (COCA) is the largest freely-available corpus of English. The corpus contains more than 560 million words of text (20 million words each year 1990-2017) and it is equally divided among spoken, fiction, popular magazines, newspapers, and academic texts.
The Corpus of Historical American English (COHA) is the largest structured corpus of historical English. COHA contains more than 400 million words of text from the 1810s-2000s and the corpus is balanced by genre decade by decade.