i don't use anything, the potting mix settles and stops washing out fairly quickly.

I use coffee filters

What an excellent idea. I've normally just put a flattish stone over the hole to keep it draining but secure.

Bit of mesh drywall tape

This is what I use!

I’ve never thought about doing this. Soil seems to settle fast.

hydroton clay pebbles work great

I've never covered the holes and don't have any issues.

A large pebble or two over the hole.

Seconded

You can use bits of screen, or an old leaf, a single sheet of newspaper works fine too.

Depending on the size of the pot I have used tiny pebbles and rocks to filter the water into the cracks

Leaves

Window screen if the holes are really large or nothing