What came before the first Commander product.

The first Commander product, Commander 2011, came out after New Phyrexia, with the Scars of Mirrodin block being infamous for creating the keyword Infect which is an incredibly powerful keyword in the Commander format, but can be argued was not designed with Commander in mind because of how it was obviously meant for 20 life formats and has never shown up as a keyword in any base commander product since its debut.

What came after the first Commander product.

Just like how powerful infect could be, after Scars of Mirrodin came the Innistrad block which would create Commander staples still used today like Blasphemous Act, Craterhoof Behemoth and Laboratory Maniac, but could you argue WoTC pushed these cards for Commander players? I don't think what Commander staples printed in a set is an apt indicator of what influence Commander has on any given Standard set, after all Avacyn Restored released Griselbrand, a card WoTC would never have created in today's Standard sets given how much the Commander format plays a role in their current set design.

How the Griselbrand standard may answer this question.

I think a more appropriate metric is to apply what I would dub the Griselbrand standard when assessing Standard sets. The Griselbrand standard is cards or mechanics that would be fine in a 20 life 1v1 block constructed format but would obviously have no business ever being in a marketed product for a 40 life multiplayer format, with other examples of the Griselbrand standard being infect, Serra Ascendant, Emrakul, the Aeons Torn, etc. Not every Standard set needs a Griselbrand-like card or mechanic to determine if the Commander format played a role in its set design. Instead, it should be asked, at what point did the Griselbrand standard die in MTG Standard set design to make way for the Commander format? I feel this is a more appropriate question to ask to determine when Commander started to take effect on Standard set design, and I'm curious to hear what set you think would best mark this transition into the Standard sets we see today.