Things like vacuums, electric kettles, etc.
Just curious why you would be running a kettle or vacuum cleaner through a relay in the first place. It is OK to have some unswitched outlets in your home...
You might want to consider these of you really need a serious relay:
Contactor Relays
Also consider using Latching Relays... They are like normal relays but don't need to stay energized to hold an on or off state... They operate more like an electronically controlled toggle switch and make the overall system more energy efficient.
Edit:
And, though more expensive than regular relays, latching relays don't draw power except during the split second when you actuate them from one position to the other. That means they generate almost no heat and are far less likely to burn your house down!