What is TSV?
CSV with tabs instead of commas, and the better choice more often than people realise. Tabs almost never appear inside a field, so the quoting rules that make CSV parsing miserable largely evaporate. Anything with prose, addresses or European decimals in it is safer as TSV.
What is HTML?
The web's document format, and incidentally a place an enormous amount of tabular data ends up - published tables that were never offered as a download. Pulling those out is usually easier than asking whoever published them for the numbers.