A simple latch I made (but ultimately chose not to use, going for a different design) for an enclosure I'm building for my printer. As is often the case, uploading simply because there's no reason not to.

Print two copies of the pin, one copy of the latch itself (the orientation in the STL / FreeCAD files assume the pin it'll hook onto is on the right; mirror it if you want the other way; the pins do not need to be mirrored). A decent amount of force is needed to attach the latch to one pin. Then, just glue them onto the door (or whatever else you want to use them on).

I printed them in PETG, I suspect it won't work too well (at least not without some sanding) in PLA.