Cable clips, panel clips and snap fits from a plain-English description, with the cable diameter, the wrap and the screw hole measured before you print.
A screw-on cable clip for a 6mm round cable, one 4mm countersunk screw hole.
A clip-on holder for a 12mm round tube, snapping on from the side, 3mm wall, with a flat back 30mm long for double-sided tape.
A panel clip for a 2mm panel, 10mm wide, that springs into a 6 x 3mm rectangular cut-out.
A clip is a spring that happens to look like a bracket. Everything that makes one work is in two numbers — how far round it wraps and how thick the wall is — and those are exactly the two numbers people leave out, because "a clip for a 6 mm cable" sounds like a complete sentence.
A cradle wants to be open. A clip wants to be closed. Both get described with the same words, and the difference between them is the only thing that decides whether the cable stays in: wrap much past two thirds and you cannot get the cable past the lips, wrap much less and it falls out. Say the fraction — "about two thirds", "roughly 240°", "half, with the opening on top" — and the arc follows from it. Leave it out and you are relying on someone else's default being the one you meant.
The example below is where this stopped being theory. Its cradle was built 130° open, which is two thirds of wrap and correct, and a check that expected every open cradle to be at least 150° open failed it. The check now reads the expectation out of the spec instead. A clip with a stated wrap gets that wrap plus or minus 20°; a clip that states none gets a band between 100° and 160°, because below the first it will not go on and above the second it will not hold.
A clip has to bend to go on and not stay bent. That is wall thickness, material and nothing else, and no measurement on this site can tell you whether the number you picked will spring back — it can only tell you the wall is the thickness you asked for. Two and a half millimetres in PETG is a reasonable starting point for a cable clip; the same clip in PLA is stiffer, more brittle, and more likely to crack the first time it is opened.
"One 4 mm countersunk screw hole" is two features, not one: a Ø4 hole and a cone at its mouth that opens to about Ø8 for an M4 head. The cone is twice the width of the hole, so a tab that comfortably fits the hole can still be too narrow for the countersink — and what you get is a feather edge where the cone runs out of material. The example below does exactly that, the print-readiness check caught it, and the page says so rather than rounding it off.
The overall envelope, the hole count and diameter, whether a countersink is actually there and what angle and face diameter it has, and how far round the cradle is open, as an angle, on the bore the kernel found. What is not measured is whether the clip springs: that is a question about the material and the load, and the report does not pretend to answer it.