Lightweight table editor

I can recommend Gnumeric.
Gnumeric is an open-source spreadsheet program. Gnumeric is...

• Free: Gnumeric and its source code are available free of charge, licensed under the terms of the GNU General Public License version 2 or version 3.
• Fast: Gnumeric starts up quickly and handles large spreadsheets while remaining responsive.
• Accurate: A spreadsheet should calculate the right answer. Gnumeric's built-in functions and tools are accurate, as several researchers have found.

To install:

sudo apt update 
sudo apt install gnumeric

pyspread

^{python FTW}

Description from pyspread‘s homepage

Pyspread is a non-traditional spreadsheet application that is based on and written in the programming language Python.

The goal of pyspread is to be the most pythonic spreadsheet.

Pyspread expects Python expressions in its grid cells, which makes a spreadsheet specific language obsolete. Each cell returns a Python object that can be accessed from other cells. These objects can represent anything including lists or matrices.

Pyspread is free software. It is released under the GPL v3. You can find the sorce code at github.

Installation

sudo apt install pyspread

If you are a user of (or at least familiar with) emacs (or vim), there is org-mode, which contain a simple integrated editor for tables. However, it needs the tables to be in a specific format, where columns are separated by vertical bars (i.e. the pipe symbol '|').

You can also do simple calculations, and the integration into the editor allows you to use the sophisticated editing facilities of emacs/vim.

Documentation can be found on the org-mode site, and a small introduction on youtube.

VIM Table Mode

Description from github repo page

An awesome automatic table creator & formatter allowing one to create neat tables as you type. The plugin is also able to format existing content into a table which makes it possible to work with csv or other text files. To get an idea of its features there's a youtube demonstration video.

Installation

See github repo page.