#1 Carrying Case
It is absolutely must to have accessories to protect earphones from getting damaged. It is the least you should do to protect your earphones.
These not only will protect the joints of your earphones but will also protect it from any breakage.
If your earphones or any other cable is not braided then you can buy this.
#2 Wire Protector
Smartphone brands are now removing 3.5mm audio jacks. It is very rare to find those nowadays.
Also to use earphones in PC you should also have 3.5mm to audio and mic splitter cable.
Sometimes we lose eartips which comes preattached on earbuds of earphones and the included eartips are either large or too small for those buying custom eartips would be a good option.
#4 Earbuds Tips
Short cables of earphones can't be connected to io ports of PC as it may be 1-3 metres away for that you can use cable extenders but remember to use the TRRS(3 ring) extender
#5 Wire Extender
If you have extra money then you can buy a cable organizer which will keep your earphones in a organized manner.
TWS anti-lost strap which makes your TWS like bluetooth neckband.