I usually dislike single-purpose tools. Single-purpose tools are either for tradesmen who do the same task repetitively, or they’re appliances that can’t be used in any other fashion.
One exception to this is the plastic hair-clog drain cleaner. It’s only useful on drains that have clogs of hair or other fibrous material, and you must have one in your abode, unless you and everyone who showers there is bald.
That’s a “Cobra Hair Snake” with an example hair-clog.
There’s several brand names, “Zip-it”, “Cobra” seem to be the most common. You absolutely have to get one. They cost less than $5. Get one that’s flat: the versions that are coiled in their packaging don’t uncoil enough to do the job.
They unclog almost all bathroom drain clogs. I’ve pulled lots of hair, hair and band-aids, and hair and hair-ties out of shower and sink drains. The packaging implies that the tools are single-use, but if you rinse them off, they’re good for months or even years.