Anatoly Lein was a Russian grandmaster who emigrated to the United States in 1976, where he was a regular presence in large Open events for about 40 years. (I saw him many times, but never played had the opportunity to play him.) While he never made it to an Interzonal, either as a representative of the USSR or the USA, he was at his peak, in the early 1970s, a very strong player rated in the world's top 30. Lein passed away a week ago; he would have been 87 at the end of this month.
While not well-known today, he took down some impressive scalps in his best years including World Champions Mikhail Tal and Vassily Smyslov, along with other top players and former Candidates like David Bronstein (twice), Lev Polugaevsky (twice), Leonid Stein, Mark Taimanov, Yuri Averbakh (twice), and Pal Benko (twice).