They may be out there, but I have never heard of anyone saying children or babies go to Hell, except a few rare times years ago when Infant Baptism proponents expressed concern for the urgency of getting infants baptized.
Nowhere do God or Jesus ever bless any nonbelievers, except children, on multiple occaisons
When heathens sacrificed their babies to Moloch, the prophet Jeremiah referred to the dead babies as “the innocents”. God even called then innocent. This means they are not condemned.
In Matthew 10, Christ receives non-believing children to Himself, against the initial steps of the disciples, even referring unclearly to the Kingdom:
13 And they brought young children to him, that he should touch them: and his disciples rebuked those that brought them. 14 But when Jesus saw it, he was much displeased, and said unto them, “Suffer the little children to come unto me, and forbid them not: for of such is the kingdom of God.” (KJV)
There is also the idea that Reformed Theology preachers have mentioned about Heaven’s variety of people as in Revelations
7:9 After this I looked, and behold, (A)a great multitude that no one could number, (B)from every nation, from all tribes and peoples and languages, standing before the throne and before the Lamb, (C)clothed in white robes, with (D)palm branches in their hands, (KJV)
This could not happen if only the normal means were available because many tribes and nations and tongues rise, flourish, fall, and become entirely and permanently extinct without a single member hearing the gospel. The Reformed explanation for how people from their tribe ended up in Heaven is that infants go to Heaven.
Maybe John MacArthur’s most widely sold book is Safe in the Arms of God: Truth from Heaven About the Death of a Child which came out right before a large industrial accident in Russia where many children died and the town somehow latched onto his book for answers about where their kids were. He expands on this idea about extinct tribes and even ones where some but very few hear the Gospel. “Non-Christian, third-world, false-religion environments have been plagued by high infant mortality, which I suspect God has been gathering little ones for their places in Heaven.” Saying that good ultimately came even from these places.