You can use “Fusion Recovery” to retrieve a Fusion Material Monster that was used with “Power Bond” or “Fusion Gate” or “Polymerization”.
You can use “Fusion Recovery” to retrieve a fusion substitute monster like “King of the Swamp” or “Goddess with the Third Eye” as long as it was used in a Fusion Summon.
“Fusion Recovery” targets 1 monster and 1 “Polymerization” in the Graveyard (so it will be negated by “Necrovalley” or “The End of Anubis”).
If 1 of the targeted cards is no longer in the Graveyard when this effect resolve, you still resolve the rest of the effect as best you can.