From Russia with Love features the return of the beloved faces from MI6 introduced in Dr. No. Bernard Lee returns as M, doing his best to keep Bond's eyes on the task and not on the women. Miss Moneypenny (Lois Maxwell) still flirts with Bond and eavesdrops on classified conversations. And although Boothroyd the gadget guru returns, he's now played by Desmond Llewelyn. Llewelyn's character is eventually called Q, a role he'd play until his death in 1999.
Finally, although she's not MI6, Bond's British fling, Sylvia Trench (Eunice Gayson) also returns from Dr. No. Trench was originally supposed to be a recurring character throughout all Bond's films (source), but From Russia with Love would mark her last appearance. No more love from Russia, or from Bond, for Sylvia.