CSV & TSV

.csv and .tsv files open with spreadsheet-style tooling on top of proper CSV/TSV syntax highlighting.

In the editor

Rainbow columns: each column is colored distinctly (cycling every eight), so rows line up at a glance. On by default; toggle in Settings → Editor → CSV or with Toggle Rainbow CSV Columns.
Field readout: the status bar shows Field N of M for the caret’s column.
Align / shrink: CSV: Align Columns (csv.align) pads fields with spaces so the delimiters line up in a monospace editor; CSV: Shrink Columns (csv.shrink) removes that padding. Both are reversible and preserve quoted fields.

The CSV Grid tool window shows the active file as a spreadsheet:

Content-fit column widths, a filter box, column sort, and inconsistent-row highlighting.
Editable cells and headers, written straight back to the file.
Right-click to Export to PDF / Print / Excel (.xlsx) / ODF (.ods).

It’s on by default for CSV/TSV files (Settings → Editor → CSV, or Toggle CSV Grid Preview).

CSV: Copy as Markdown Table (csv.copyAsMarkdownTable) copies the whole file as a GFM table.
From a Markdown table, convert to and from CSV (markdown.tableFromCsv / markdown.tableToCsv) or export it to CSV, Excel, or ODF (see the Markdown guide).