The Crack Weeder which is also known as a patio knife and it’s amazing and very efficient at getting the weeds out from between paving stones that are otherwise unreachable with other tools. I own one of these tools and I use it for weeds between stones and many other tasks too. It’s very versatile and a little bit dangerous when it’s new.
The blade is very sharp on one side which is needed for narrow crevices but it can cut you if you’re not careful.
I’ve used it for moving paving stones, it’s great for leverage in lifting heavy stones and pavers. Once lifted it works as a scraper to get the soil off of the bottom of the rock. It’s useful for breaking up hard soil and mixing in soil amendments too.
This is a great gift to give a gardener, they will love it and find many uses for it in no time!