The bulk update request #11413 is pending approval.

create alias pool_toys (0) -> pool_toy (5821)
create alias pooltoys (0) -> pool_toy (5821)

Reason: Second verse, same as the first

Aliases away pluralizations of the pool_toy tag. Interestingly, the no-space version is more common here:
https://e621.net/post_versions?commit=Search&search%5Btags_added%5D=pool_toys
https://e621.net/post_versions?commit=Search&search%5Btags_added%5D=pooltoys