In my design, I am using the "2mm TestPoint". This is not what you want, as it is just designed for touching with a meter probe, not something you can hook a probe too.
I have seen boards with surface mount test points that kind of look like tiny little suitcase handles. The appropriate scope probes can easily and robustly lock on to that kind of test point. I've seen those inside expensive equipment as test points for calibration. They did not appear to be low cost, but I've never researched them.
If you get a scope probe designed to lock onto a via, then vias would be a low cost option. If you create a part that is a via, then you can have the test points show up in your schematic.
For through hole designs, a bare loop of wire works. It can either be a U shaped wire soldered into two near by holes, or a wire shaped liked an eye bolt, with only one hole. I haven't seen the eye bolt style used in modern equipment, but it was popular many years ago. When something fades away like that, it is generally a sign that it wasn't so good in practice.
There are plenty of scope probes designed for .1" headers. If you have the board real estate for them, and you don't mind through hole parts, then standard headers make a lot of sense.
In any case, remember to include ground connections near the signal connections.