Thunder was a weekly anthology title published by IPC between 1970 and 1971, and lasted for just 22 issues. Strips featured included Adam Eterno, Black Max, Steel Commando and The Spooks of St. Lukes. It was merged into Lion. Sadly, the name of the composite comic wasn't Thunder Lion.
Thunder Annuals were published from 1971-1973, dated 1972-1974.