I tried Libreoffice, but its Import option while pasting in the cell is very annoying.I also tried Gnumeric but I am not able to paste using middle button.Parcellite to make copy paste faster and middle button pasting is not working with Gnumeric. Is there any simple table maker app available that can accept only simple unformatted text? All these software are very complicated for this simple work.
In LibreOffice Calc, press F2 and then paste. This is similar to your answer in the comments but uses an extra keystroke instead of double-clicking.
Alternatively, a reliable 2 key combination method is to press Ctrl+Shift+V and then Enter to paste unformatted.
In Writer, this can be done with a single key combination, Ctrl+Shift+Alt+V. However, Calc seems better suited to your needs, and this combination does not work in Calc.
Note that on Windows, no import dialog is displayed. Instead, it is pasted as HTML instead of plain text by default.