Nice builds but….

The author is pretty risky with the first one (2nd block fence for tablesaw) and how close the blade is to the fence, I would use a scrap board on the fence myself. The second build is a jigsaw template follower, acts like a router bit with a bearing, nice idea. Third build is a a jig to move small parts on a router table. Nice but seems a bit overkill. Fourth build is a simple centering jig for a drillpress. This one is a clever build. The last item is a contour duplicator. My 2 cents, buy this one at Harbor Freight for $8.

https://www.homemadetools.net/forum/5-amazing-woodworking-tools-hacks-%7C-tips-tricks-88424?homelistings#post192803