The mycosynth created the groove. The groove created the party.

Mycosynth Wellspring

When Mycosynth Wellspring enters or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Secret Lair Drop

The oil created the mycosynth. The mycosynth created New Phyrexia.

The Brothers' War Commander

When Mycosynth Wellspring enters the battlefield or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Commander 2021

Commander Anthology Volume II

When Mycosynth Wellspring enters the battlefield or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle your library.

The ability will trigger when Mycosynth Wellspring is put into a graveyard from the battlefield, even if the ability that triggered when it entered hasn't resolved yet.