Many of the clipboard enhancers offer permanent clips - freeware ones include
ClipCache 1.41 and
ArsClip. "Big" ones like
ClipMagic keep everything permanently anyway, unless you set automatic purge features, and you could set a specific group. Kevin Solway's
ClipText is a bit like a more limited version of Multi Clipboard mentioned by tinjaw above.
Alternative approaches -
PowerPro's snippets, or a keyword-driven system like
Type Pilot, shareware, or their freeware but less-featured version, Speed Pilot. Or
AutoHotkey's hotstrings.