Well, for merely commissioners that moved from the commission to those positions, the first example that comes to my mind is the head of the EU Commission during the 2008 Crash and it's aftermath, who went to Goldman Sachs afterwards and is still there today as a non-executive president.

During his time in the Commission they were very pro-Finance in the way they handled the aftermath of the Crash with him personally pushing frequently for measures were EU money was used to unconditionally helped the interests of large Financial Industry companies, and Goldman Sachs is one of the largest companies and massively benefited from, amongst other things, near-defaulting Greek Treasuries being bought from the private sector by the EU, which subsequently forced the Greeks into Austerity to as much as possible pay those Treasuries.

There's even a scandal with him were, whilst working at Goldman Sachs, he broke the EU rules on lobbying by using his access card to EU buildings - which he was entitled to have as an ex-Head of the Commission - to simply enter into those buildings and waltz over to the offices of sitting EU officials to lobby for Goldman Sachs. The EU ended up revoking his access privileges, the first and only time that has happened for an ex-EU Commissioner.