Effective altruism has different roots than the rationalists (although, yes, the 2 communities have become close over the years). I have seen any statement by Sam Bankman-Fried where he identified as a rationalist.
Well, if we're ignoring everyone else's descriptions of SBF, Caroline Ellison had a tumblr on which she repeatedly self-identified as a rationalist: https://caroline.milkyeggs.com/worldoptimization