1. Williams-Mercedes in 1995 (as it was stated by Norbert Haug in 2018 https://www.racefans.net/2018/07/23/pad ... -day-four/ (go to 12:30pm section) - and elected to stay with Renault and thus Mercedes went on to McLaren)
2. Minardi-Mugen Honda in 1996 (and later Minardi elected to stay with Ford)
Any additions?