Saline nasal spray and vapour rub (on chest and back) have been good for us (or certainly haven’t done any harm). We’ve also used the vapour oil drops in a bowl of warm water in the bedroom but not sure if it genuinely made a difference or not x
Definitely get a humidifier for the bedrooms, it really helps when the air is dry and sinuses are blocked up
The calpol plugins. Not cheap though.