Many households develop routines and responsibilities over time. Often those responsibilities are not volunteered for as much as they just "fall" on someone to do. Offer to do a chore or just do it anonymously.
Routines can become tedious and unappreciated tasks. It is uplifting when those efforts are acknowledged and appreciated. And it can really put a smile on someone's face if you occasionally just do a chore that someone else in the household normally does. It demonstrates appreciation and acknowledges their efforts as well as relieves them for a time. It can be especially helpful if the person is extra busy or stressed for other reasons. Here are some examples of typical household chores:
Offer to take over a task permanently. Imagine the surprise and joy of a parent when a child offers to clear the dishes from now on. Or offer to do a large-scale task that everyone dreads. Things like "clean the garage" or organize a messy room or storage space.
If you see someone wrapping up a trash bag offer to take it outside or replace the bag. Or just pitch in when someone else is making a meal.
Pitching in and changing up the routine will go a long way toward strengthening family and household relationships. It says "I know you work hard - let me help you". It can also be a big relief in times of stress or when someone is under a time crunch.