Clipboard manager with "history paste" support?

I'm not aware of a clipboard manager that itself provides the feature you want, but there are two ways in which I imagine that Klipper could be incorporated in a solution.

1. Klipper offers "Next History Item" and "Previous History Item" shortcuts that change the order of the clipboard history. Therefore, pasting the nth entry can be done by running the "Next History Item" shortcut n times, then running Ctrl+V (or whatever your paste shortcut is), and then -- to put the history back into its original order -- running the "Previous History Item" shortcut n times. Using this, your problem reduces to setting a shortcut that simulates entering a series of shortcuts.
2. The command qdbus org.kde.klipper /klipper getClipboardHistoryItem n where the n at the end is a number (e.g. 0, 1, 2...) will output the nth clipboard history item. Using this, your problem reduces to the problem of setting a keyboard shortcut that will paste the output of a command.

When Keepboard is activated, the second item in the history is selected by default (because the top item is in the clipboard anyway and can be pasted directly without activating clipboard manager). Thus you can quickly paste the second item by using Keepboard activation hotkey and pressing Enter right away.

GPaste is a clipboard management system for GNOME. GPaste manages clipboard history and allows easy access to it using keyboard shortcuts, gnome-shell extension and command-line tools.

To install GPaste in all currently supported versions of Ubuntu open the terminal and type:

sudo apt install gpaste

Qlipper is a lightweight clipboard history applet. It provides the following features:

• saves clipboard history entries and restores them
• lightweight
• system tray docking app
• few requirements
• can be used in GNOME

To install Qlipper in all currently supported versions of Ubuntu open the terminal and type:

sudo apt install qlipper

CopyQ is an advanced clipboard manager with editing and scripting features. CopyQ monitors the system clipboard and saves its content in customized tabs. Saved clipboard entries can be later copied and pasted directly into any application.

To install CopyQ in Ubuntu 18.04 and later open the terminal and type:

sudo apt install copyq