Q:

Why were there so many Daisy Johnson LMDs?

In Marvel's Agents of SHIELD, Season 4, Episode 15 "Self Control", SHIELD is infiltrated by LMDs (Life Model Decoys) with specific agents replicated and replaced.
Daisy finds twenty LMDs of herself, all in standby mode and all in one room.
Why would AIDA build so many Daisy LMDs?

A:

The goal of the Daisy LMDs was to kill the Inhumans. To avoid suspicion and the Inhumans contacting each other more Daisys can be used at once to kill the Inhumans at the same time.

In the meantime, Daisy will contact the Inhumans, inform them she's coming to collect them personally.
Yes. And then execute them on sight.
Agents of S.H.I.E.L.D., Season 4 Episode 15, "Self Control"

