The most common and most likely answer to this crossword clue is the 5 letter word YOYOS
I've seen this crossword clue in The Guardian
Y
O
Y
O
S
Buddy explains!

The straight part
We know that "toys" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case toys = yoyos.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does YOYOS mean?
YOYOS noun- A toy consisting of a spheroidal or cylindrical spindle having a circular groove in which string is wound; it is used by holding the string in the fingers and reeling the spindle up and down by movements of the wrist.
- A volatile market that moves up and down.
- Someone who vacillates.
- A cloth rosette formed by gathering the outside edge of a circle of fabric in toward the centre using a running stitch.
- A foolish, annoying or incompetent person.