Maybe something like this?: http://www.christmascentral.com/p-253111-40ct-outdoor-gutter-hooks-for-hanging-christmas-lights.aspx?CAWELAID=220010480000335706&catargetid=1614140047&cadevice=c&cagpspn=pla-&gclid=CJ-c2ryV2bsCFed0Qgod4WIAWQ
Do a google search for "gutter christmas light hangers" or...