In addition to the regular corpus interface, there are a wide range of other corpus-based resources, some of which allow you to download large amounts of data for offline use. (Compare to academic license)

Full-text Download full-text data for iWeb, COCA, COHA, GloWbE, NOW, Coronavirus, Wikipedia, SOAP, the TV Corpus, the Movies Corpus. With this data, you will have the texts from the corpora on your own computer, rather than having to use the web interface. The data comes in three formats: relational database, word/lemma/PoS (vertical format), or text (linear format).
Word Frequency Download lists of the top 60,000 lemmas in COCA, including the frequency by the eight main genres and nearly 100 sub-genres. You can also download a list with the frequency of the word forms (e.g. decide, decides, deciding, decided), as well as a list of the top 219,000 words (not lemmas) in COCA, including frequency by genre.
Collocates Download lists with the top 200-300 collocates (nearby words) for 60,000 different lemmas -- 13,500,000 node/collocate pairs in all.
N-grams Download lists (in various formats) of all 2, 3, 4, and 5-word strings that occur at least four times in COCA -- more than 40 million n-grams in total.
Academic Vocabulary Download free lists from the 120 million words of COCA-Academic texts, including academic words grouped by word families, lists of "core" academic English, and "technical" word lists for the nine domains of COCA-Academic (e.g. Law, Medicine, or Business).
iWeb All of the resources listed above are for COCA and other "smaller" corpora (e.g. 100 million - two billion words in size). You can also access data from the 14 billion word iWeb corpus, which has its own full-text, word frequency, collocates, and n-grams data.