I fouled the quoting bit up but as far as ITC actors go:
off the top of my head, Ed Bishop (who by DAF had voiced in Captain Scarlet, then starred in UFO, Protectors etc), Shane Rimmer (much of Gerry Anderson's stuff plus Persuaders and so on), David Healy (Whyte's satellite mission commander, likewise some of Anderson's shows and beyond), Charles Gray, Peter Burton (Dr No's Q), Laurence Naismith, Richard Vernon and I would even argue Lois Maxwell (voiced Atlanta in Stingray, appeared in the Saint and other ITC shows), Bernard Lee did a share of ITC stuff (incl Persuaders) and let's be honest the biggest one perhaps is Sir Roge.
I grew up watching these shows and these faces are far too familiar to me by now and so seeing them in the early Bonds warms in its way. Especially those who did Gerry Anderson's shows from say Stingray through to Space 1999.