Recently Dieter Lamm (b. 1955) and Dave Causey (b. 1930) passed away. They had in common that they had twin brothers: Charly Lamm (still alive) resp. Dean Causey (died in 1987). BTW, Dave and Dean were born in Rhode Island but were adopted by the wealthy Causey family of Indiana.
From my records in motor racing there are/were also these twin siblings:
Aldo & Mario Andretti (USA, b. 1940)
Neal & Rick Bates (Australia, b. 1965)
Stefano & Valter Benazzato (Italy, b. 1956)
Ahmed & Samir Benbekhti (France, b. 1965)
Alexander & Caroline Bender (Sweden, b. 1990)
Roger & Roland Bervillé (France, b. 1966)
Arnold & Raymond Burton (England, b. 1917)
Dennis & Marc Busch (Germany, b. 1987)
Pedro & Victor Calado (Portugal, b. 1971)
Pietro & Silvia Castelli (Italy, b. 1977)
Mike & Ted Christopher (USA, b. 1958)
Amber & Angela Cope (USA, b. 1983)
Tim & Tom Coronel (Netherlands, b. 1972)
Piergiorgio & Romeo Deila (Italy, b. 1966)
Alan & Mike Domingo (South Africa, b. 1946)
Joel & Jon Field (USA, b. 1955)
David & Markus Finger (Switzerland, b. 1984)
Brian & Mike Finney (USA, b. 1977)
Alexandre & Gustavo Foizer (Brazil, b. 1986)
Heinz-Otto & Jürgen Fritzsche (Germany, b. 1955)
Andreas & Markus Gummerer (Italy, b. 1986)
Kara & Kenny Hendrick (USA, b. 1969)
Günther & Heinz Hennerici (Germany, b. 1924)
(Billy &) Tommy Hitchcock (USA, b. 1939)
David & Godfrey Jones (England, b. 1953)
Markus & Thomas Kern (Germany, b. 1989)
Masayuki & Muneyuki Kurihara (Japan, b. 1982)
Aldo & Dario de Lorenzo (Italy, b. 1957)
Phil & Steve Mahre (USA, b. 1957)
Donald & Erle Morley (England, b. 1930)
Denis & Sascha Morozov (Liechtenstein, b. 1980)
Jens & Peder Nylin (Sweden, b. 1987)
Laurent & Stan d’Oultremont (USA, b. 1969)
Alfred & Robert Renauer (Germany, b. 1985)
Niki & Valentino Sebastiani (Italy, b. 1986)
Hiroyoshi & Yuki Shibata (Japan, b. 1982)
Brian & Mark Simo (USA, b. 1959)
Ricardo & Rodrigo Sperafico (Brazil, b. 1979)
Francis & Freelan Stanley (USA, b. 1849)
Larry & Lee Taylor (USA, b. 1943)
Bo & Hans Thorszelius (Sweden, b. 1944)
Jerry & Louie Unser (USA, b. 1932)
Rolando & Silvio Vaglio (Switzerland, b. 1939)
Jérôme & Julien Vigna (France, b. 1987)
Federico & Javier Villagra (Argentina, b. 1969)
Richard & Robert Yates (USA, b. 1943)